As with the planets list, this list is based on the Star Trek : Encyclopedia but contains some small changes. I have removed those names which are proper names of individuals - for example the empathic 'Gem' from the original series episode "The Empath" has been deleted, as has Data's cat 'Spot'. Also gone are alternate names for species mentioned elsewhere on the list - the Encyclopedia list has an entry for "Ugly Bags Of Mostly Water", the Microbrain name for Humans, but this is redundant since Humans are mentioned under their own name. Finally, Borg species numbers have been moved from their own entries into the description of the individual species where we have names for those (Talaxians, Vulcans, Kazon).

After these changes the list has four hundred and fifty seven species listed on it.
 

Name	Description	Series	Episode
Acamarians	Humanoids from Acamar III	TNG	"The Vengeance Factor"
Akritiri	Delta quadrant society who jailed people on space stations	VOY	"The Chute"
Alcyones	People who destroyed the second to last Tarellian plague vessel	TNG	"Haven"
Aldeans	Humanoids who inhabit the planet Aldea, long thought mythical	TNG	"When the Bough Breaks"
Aldebarran Serpent	Reptilian life form with three heads	TNG	"Hide and Q"
Algorian Mammoth	Large creature	DS9	"The Wire"
Allasomorph	Shape shifting sentient lifeform	TNG	"The Dauphin"
Alvanian Cave Sloth	Creature well known for sleeping very soundly	DS9	"The Sword of Kahless"
Alvanian Spine Mite	Small creatures which live in the spines of other beings	DS9	"The Begotten"
Alverian Dung Beetle	Insect	DS9	"Apocalypse Rising"
Amoeba	Single celled life form up to many thousands of miles long	TOS	"The Immunity Syndrome"
Amphibian	Any creature which can live on both land and water	TNG	"Genesis"
Anaphasic life forms	Energy creature which lived within a candle flame	TNG	"Sub Rosa"
Andorian Amoeba	Single celled life form native to Andoria	VOY	"Tuvix"
Andorians	Sentient humanoids with blue skin, white hair and two antennae	TOS	"Journey to Babel"
Angosians	Sentient humanoids who created "perfect" soldiers	TNG	"The Hunted"
Antedeans	Sentient piscine life forms	TNG	"Manhunt"
Anticans	Lupine sentients native to Antica	TNG	"Lonely Among Us"
Apollo	Being once worshipped as a god on Earth	TOS	"Who Mourns For Adonis"
Arachnid	Creature which Barclay de-evolved into	TNG	"Genesis"
Arbazan	Federation member species	DS9	"Forsaken
Arbazon Vulture	A predatory bird	DS9	"The Search Part II"
Argellians	Sentient humanoids, native to Argelius II	TOS	"Wolf In The Fold"
Argosian	Sentient species; Sisko once almost got into a fight with one	DS9	"Dax"
Argrathi	Humanoid society who are native to Argratha	DS9	"Hard Time"
Arkarian Water Fowl	Creature noted for its unusual mating habits	TNG	"Starship Mine"
Armus	Being created when a species learned to transfer their negative feelings into a physical form	TNG	"Skin of Evil"
Arritheans	Delta Quadrant species who engaged in trade with Voyager	VOY	"Revulsion"
Australopithecine	Early hominid which Riker de-evolved into	TNG	"Genesis"
Bacillus Spray	Creature used to attack grapevine parasites	TNG	"All Good Things"
Bajoran Shrimp	Animal native to Bajor	DS9	"You Are Cordially invited"
Bajorans	Sentient humanoids native to the planet Bajor	TNG	"Ensign Ro"
Ba'ku	Humanoid species who have almost eternal youth thanks to their planets rings	Star Trek : Insurrection
Balduk Warriors	Species known for their ferocity	TNG	"New Ground"
Bandi	Humanoid species who built the Farpoint Starbase	TNG	"Encounter At Farpoint"
Baneans	Sentient Delta Quadrant civilisation	VOY	"Ex Post Facto"
Baneriam Hawk	Predatory bird	DS9	"If Wishes Were horses"
Bardakian Pronghorn Moose	Animal famed for its exceptionally loud call	TNG	"Unification"
Barkonians	Humanoid species approximately equal in technology to Earth in the Renaissance	TNG	"Thine Own Self"
Barolians	Humanoids who traded with Romulans	TNG	"Unification"
Barrowbug	Insect native to Bajor	DS9	"Ties Of Blood And Water"
Barzans	Humanoid sentients who discovered the Barzan wormhole	TNG	"The Price"
Bat	Flying rodent native to Terra. Similar animals are found on other planets	DS9	"The Reckoning"
Beauregard	Plant cared for by Sulu on the USS Enterprise	TOS	"The Man Trap"
Belzoidian Flea	Creature familiar to Q	TNG	"Deja Q"
Benthans	Delta Quadrant society who were testing a coaxial warp core	VOY	"Vis a Vis"
Benzites	Sentient humanoids who live in caves	TNG	"Coming of Age"
Berellians	Sentient species known as being poor engineers	TNG	"Redemption Part II"
Berserker Cat	Felinoid known for its great courage	DS9	"Let He Who Is Without Sin"
Beta Runner Cloud	Sentient gaseous being which lived in deep space but was able to posses a Humanoid body	TNG	"Lonely Among Us"
Beta XII-A Entity	Life form which fed on fear	TOS	"Day of the Dove"
Betazoids	Telepathic humanoids native to Betazed; Federation members	TNG	"Haven"
Bok-rat	Klingon rodent	DS9	"Soldiers Of The Empire"
Bolians	Sentient humanoids with blue skin	TNG	"Allegiance"
B'omar	Delta Quadrant species who are paranoid about allowing others into their territory	VOY	"The Raven"
Boraalans	Primitive inhabitants of Boraal II	TNG	"Homeward"
Borg	Powerful species composed of cybernetic humanoids with linked minds	TNG	"Q Who?"
Borgia Plant	Poisonous plant native to planet M-113	TOS	"The Man Trap"
Boslics	Sentient humanoid civilisation	DS9	"Sons of Mogh"
Botha	Delta Quadrant society	VOY	"Persistence of Vision"
Breen	Mysterious species who allied with the Dominion during the war with the Alliance	TNG	"Hero Worship"
Brekkians	Humanoid civilisation native to the planet Brekka	TNG	"Symbiosis"
Bringloidi	Oirish Humans who colonised the planet Bringloid V	TNG	"Up The Long Ladder"
Briori	Humanoid species native to the Delta Quadrant	VOY	"The 37's"
Bunny Rabbit	Earth animal sometimes imagined in the shape of nebula clouds	TNG	"Imaginary Friend"
Bynars	Humanoid species who have become highly dependant on computers	TNG	"11001001"
Caatati	Humanoid civilisation largely assimilated by the Borg	VOY	"Day of Honor"
Calamarain	Energy being which had a grudge against Q	TNG	"Deja Q"
Caldonians	Large Humanoid species which attempted to buy the Barzan Wormhole	TNG	"The Price"
Caldorian Eel	Animal which was once discovered on a junked spacecraft	TNG	"Unification, Part I"
Camorites	Humanoid species native to Camor V	TNG	"Bloodlines"
Capellans	Fierce but primitive warrior race	TOS	"Friday's Child"
Cardassians	One of the Alpha Quadrants major powers	TNG	"The Wounded"
Carnivorous Rastipod	Large Bajoran creature known for its clumsiness	DS9	"Progress"
Cat	Terran animal noted for its independence	TNG	"Data's Day"
Cave-Rat	Cave dwelling animal	DS9	"The Sword of Kahless"
Ceti Eel	Sluglike creature which burrows into a persons ear	Star Trek II : The Wrath of Khan
Chalnoth	Lupine sentients native to Chalna	TNG	"Allegiance"
Chameloid	Shape changing beings once thought to be mythical	Star Trek VI : The Undiscovered Country
Chrysallians	Species who attempted to buy the Barzan Wormhole	TNG	"The Price"
Circassian Cat	Geordi LaForge owned one of these	TNG	"Violations"
Coalescent Organism	Life form which could absorb other entities and assume their identity	TNG	"Aquiel"
Colyus	Sentient holograms on Yadera II	DS9	"Shadowplay"
Companion	Energy being which was in love with Zephram Cochrane	TOS	"Metamorphosis"
Conciousness Parasite	Noncorporeal lifeform which attacks a victim just before death	VOY	"Coda"
Corvan Gilvos	Stick like animal which is now endangered	TNG	"New Ground"
Cove Palm	Plant which is poisonous	TNG	"Brothers"
Cravic	Now extinct Delta Quadrant species	VOY	"Prototype"
Crystalline Entity	Large spacedwelling lifeform which can destroy life on a planetary scale	TNG	"Datalore"
Crystilia	Flowering plant found on Tele-Marius III	TNG	"In Theory"
Cyperon Cactus	Plant found in the E-D arboretum	TNG	"Genesis"
Cypriprdium	Earth plant	VOY	"Tatoo"
Cytherians	Advanced species which lives near the center of the galaxy	TNG	"The N'th Degree"
Dachlyds	Picard mediated a dispute involving this species	TNG	"Captain's Holiday"
Daliwakan	Humanoid species	VOY	"The Cloud"
Dal'Rok	Mysterious creature which periodically threatens a Bajoran village	DS9	"The Storyteller"
Dalvin Hissing Beetle	Small beetle which hisses	TNG	"Parallels"
D'Arsay	Ancient civilisation	TNG	"Masks"
Debrune	Ancient offshoot of the Romulans	TNG	"Gambit, Part I"
Degebian Mountain Goat	Animal known for its ability to climb	DS9	"The Sword of Kahless"
Deltans	Humanoid species	Star Trek : The Motion Picture
Demons	Life form composed of a metallic liquid containing Deuterium	VOY	"Demon"
Denebian Slime Devil	Unpleasant creature once compared to James Kirk	TOS	"The Troubble With Tribbles"
Denebians	Species who dealt with Harcourt Fenton Mudd	TOS	"I, Mudd"
Denevan Neural Parasite	Large single celled organisms which spread from planet to planet causing mass insanity	TOS	"Operation : Annhilate!"
Devidians	Parasitic species which fed off Human neural energy	TNG	"Time's Arrow, Part I"
Dikironium Cloud Creature	Gaseous life form which feeds on Human blood	TOS	"Obsession"
Diomedian Scarlet Moss	Plant	TNG	"Clues"
Distortion ring Being	Mysterious entity(s) which inhabit a twisted region of space	VOY	"Twisted"
Doosodarians	Ancient civilisation	TNG	"Interface"
Doptarians	Distant relatives of the Ferengi	DS9	"The Foresaken"
Dosi	Species native to the Gamma Quadrant	DS9	"Rules of Acquisition"
Douwd	An immortal being of tricks and disguises; a Douwd rendered the Husnock extinct	TNG	"The Survivors"
Drabidium Calimus	Plant similar to a Terran violet	TNG	"Rascals"
Draco Lizards	Flying terran Lizard	TNG	"New Ground"
Drathan Puppy Lig	Animal sometimes kept as a pet	DS9	"Crossover"
Drayans	Species native to the Delta Quadrant	VOY	"Innocence"
Dream Species	Delta Quadrant species whose consciousness existed only in sleep	VOY	"Waking Moments"
Drella	Creature which sustains itself on the emotion of love	TOS	"Wolf in the Fold"
Dryworm	Giant creature on Antos IV which can produce and use energy without harming itself	TOS	"Who Mourns For Adonis"
Edo	A Humanoid species who have a primitive society on Rubicun III	TNG	"Justice"
Edo God	A powerful being which cares for the Edo people	TNG	"Justice"
Eel-birds	Creatures which feel an overwhelming urge to return to the place of their birth in order to reproduce	TOS	"Amok Time"
Ekosians	Humanoid civilisation native to the planet Ekos	TOS	"Patterns of Force"
Elasians	Warrior species from Elas	TOS	"Elaan of Troyus"
El-Aurians	Civilisation of 'listeners' who were nearly wiped out by the Borg	Star Trek : Generations
Elaysians	Humanoid species whose planet has virtually no gravity	DS9	"Melora"
Ellora	Species conquered by the Son'a and used as a labour force	Star Trek : Insurrection
Emergent life form	Life form created by the Enterprise-D when it briefly attained sentience	TNG	"Emergence"
Enarans	Species native to the Delta Quadrant	VOY	"Remember"
Ennis / Nol-Ennis	Two groups confined to a prison moon to fight for all time	DS9	"Battle Lines"
Entabans	Delta Quadrant species which was highly reluctant to permit ships to enter their space	VOY	"Vis a Vis"
Entharans	Delta Quadrant species which relied heavily on trade with alien cultures	VOY	"Retrospect"
Eryops	Extinct animal species, the last common ancestor of warm and cold blooded life on Earth	VOY	"Distant Origin"
Etanian Order	Species native to the Delta Quadrant	VOY	"Rise"
Evora	Technologically advanced civilisation which was considered as a Federation protectorate shortly after achieving space flight	Star Trek : Insurrection
Excalbian	Intelligent rocks which conducted a study of good and evil	TOS	"The Savage Curtain"
Exocomp	Artificial life forms	TNG	"The Quality of Life"
Eymorg / Morg	The females and males of the same species who reside on Sigma Draconis VI	TOS	"Spock's Brain"
Fabrini	Builders of the asteroid ship Yonada	VOY	"For The World Is Hollow And I Have Touched The Sky"
Farn	Humanoid civilisation native to the Delta Quadrant. Some were assimilated by the Borg	VOY	"Unity"
Farpoint Station	Form assumed by a large shapeshifting space based lifeform when it was injured	TNG	"Encounter At Farpoint"
Felaran Rose	Plant found on a planet in the Delta Quadrant	VOY	"Paturition"
Ferengi	Alpha Quadrant species who are largely motivated by avarice	TNG	"The Last Outpost"
Fire Ants	Poisonous insect native to Terra	VOY	"The Chute"
Fire Beast of Sullus	Creature from the myths of the Drayos	VOY	"Innocence"
Fire Snakes	Reptile species	VOY	"Fair Trade"
Flitter Bird	Avians native to Rhymus Major	DS9	"Profit And Loss"
Folnar Jewel Plant	Plant which produces a resin which sets to form a gemstone	TNG	"Dark Page"
Founders	Shapeshifting liquid species native to the gamma Quadrant	DS9	"The Search, Parts I & II"
Frunalian	Alpha Quadrant species	DS9	"Emissary"
Galipotans	Civilisation known for keeping a different standard of time to most	DS9	"The Wire"
Gallamite	Species famed for having transparent skulls. Dax once dated a Gallamite	DS9	"The Maquis, Part I"
Garanian Bolites	Small creatures which cause intense itching and extreme skin colour changes when they bite	DS9	"A Man Alone"
Garili Tree	Plant found on the Vhnori homeworld	VOY	"Emanations"
Garlanic Tree	Plant native to the Elaysian home planet	DS9	"Melora"
Gatherers	Nomadic people who split off from the Acamarians; they have now been reabsorbed	TNG	"The Vengeance factor"
Glob fly	Insect known for being very small, completely harmless, and extremely irritating	TNG	"The Outrageous Okona"
Golanans	Technologically advanced Alpha Quadrant civilisation who died out approximately 1,000 years ago	DS9	"Prodigal Daughter"
Gomtuu	One of a species of organic spacecraft which once numbered in the millions	TNG	"Tin Man"
Gorgan	Noncorporeal lifeform which killed the adults of the Starnes Expedition	TOS	"And The Children Shall Lead"
Gorn	Immensely strong reptilian species which once attacked a Federation outpost	TOS	"Arena"
Gorokian Midwife Toad	Animal life form	VOY	"Death Wish"
Grazerite	Humanoid species which evolved from herd animals	DS9	"Homefront"
Gree	Species native to the Delta Quadrant	VOY	"Elogium"
Grisella	Species which hibernates for long periods	TNG	"The Ensigns of Command"
Gulgallian Rat	Creature which scared Wesley Crusher	TNG	"Coming of Age"
Gunji Jackdaw	Bird similar to a Terran Ostrich	DS9	"If Wishes Were Horses"
Haakonians	Humanoid species from the Delta Quadrant	VOY	"Jetrel"
Hadrosaur	Terran cretaceous dinosaur, ancestor of the Voth	VOY	"Distant Origin"
Halkans	Primitive Humanoid civilisation who have a philosophy of total peace	TOS	"Mirror, Mirror"
Hanonian Land Eel	Large carnivore native to Hanon IV	VOY	"Basics, Part I"
Hara cat	Life form native to the Bajoran system	DS9	"Second Skin"
Hill People	Primitive hunter-gatherers who warred with the Village People	TOS	"A Private Little War"
Hirogen	Technologically advanced species dedicated to hunting	VOY	"Hunters"
Horta	Rock creature which looks like a Pizza	TOS	"The Devil In The Dark"
Humans	Powerful Alpha Quadrant species	Star Trek
Humpback Whale	Species of whale native to Earth; hunted to extinction in the past, now repopulated via time travel	Star Trek IV : The Voyage Home
humuhumunukunukuapua'a	Terran fish	TNG	"Rascals"
Hunters	Species native to the Gamma Quadrant who hunt the Tosk	DS9	"Captive Persuit"
Hupyrians	Species known for their devotion to those who employ them	DS9	"The Nagus"
Husnock	A species of "hideous intelligence", rendered extinct by a Douwd	TNG	"The Survivors"
Iconians	Ancient and highly advanced species now extinct	TNG	"Contagion"
Idanians	Humanoid species	DS9	"A Simple Investigation"
Iguana	Terran reptile	TNG	"Genesis"
Ilidarians	Delta Quadrant civilisation	VOY	"Cathexis"
Inheritors	Name for a group of Humans visited by an alien civilisation some centuries ago	VOY	"Tattoo"
Interphasic Organisms	Parasitical life forms which infested the Enterprise D	TNG	"Phantasms
Iothra	Species which breathes hydrogen	DS9	"Melora"
Iotians	Humanoid species with an instinct for mimicry	TOS	"A Piece Of The Action"
Isis	Life form of unknown origin, apparently a shapeshifter	TOS	"Assignment Earth"
Jarada	Insectoid civilisation who are fanatical about etiquette	TNG	"The Big Goodbye"
Jem'Hadar	Genetically engineered species created as soldiers for the Dominion	DS9	"The Jem'Hadar"
J'naii	Humanoid species who denied the concept of gender	TNG	"The Outcast"
Joranian Ostrich	Life form known for dipping its head under water when threatened, often until it drowns	DS9	"Past Prologue"
Junior	Spaceborn lifeform which thought the Enterprise D was its mother	TNG	"Galaxy's Child"
Kalandans	People who built an artificial planet, but were killed off by a disease	TOS	"That Which Survives"
Karemma	Gamma Quadrant civilisation known as traders	DS9	"Rules Of Acquisition"
Kavarian tiger-bat	Animal from the planet Kavaria	DS9	"For The Cause"
Kazon	Humanoid Delta Quadrant civilisation; deemed unworthy of assimilation by the Borg. Borg designation Species 329	VOY	"Caretaker"
Kellerun	Civilisation at war with the T'Lani for centuries	DS9	"Armageddon Game"
Kelvans	Species from the Andromeda galaxy	TOS	"A Rose By Any Other Name"
Kerelian	Species known for its highly sensitive hearing	TNG	"Lessons"
Kes	People from the planet Kesprytt III who applied for Federation membership	TNG	"Attached"
Klabnian Eel	Species which Q did not like	TNG	"QPid"
Klingons	Major species native to the Alpha and Beta Quadrants	TOS	"Errand Of Mercy"
Koblian	Species which was dying out and required Deuridium to prolong their lives	DS9	"The Passenger"
Kohms	Humanoid residents of Omega IV	TOS	"The Omega Glory"
Koinonians	Noncorporeal lifeform which took Human form	TNG	"The Bonding"
Kolar Beast	Klingon animal	Star Trek : Insurrection
Kradin	Delta Quadrant civilisation who were at war with the Vori in 2365	VOY	"Nemesis"
Krallinian Eel	Creature native to the Delta Quadrant	VOY	"Jetrel"
Krellans	Civilisation whose food was popular with other planets, especially Farius Prime	DS9	"Honor Among Thieves"
Krenim	Delta Quadrant civilisation who used temporal weaponry in some timelines	VOY	"Year Of Hell. Parts I & II"
Kressari	Reptilian species	DS9	"The Circle"
Kryonian Tiger	Creature found in the Brentalia Zoo	TNG	"Imaginary Friend"
Ktarians	Species which attempted to subvert Starfleet via an addictive game	TNG	"The Game"
Kyrians	Delta quadrant civilisation who went to war with the Vaskans while Voyager was passing by	VOY	"Living Witness"
Lapling	Highly endangered species; the last surviving member was owned by Kivas Fajo	TNG	"The Most Toys"
Lavaflies	Insect lifeform of large size, native to Talax	VOY	"Macrocosm"
LB10445	Single celled life form	TNG	"Time's Arrow, Part II"
Leaf Miners	Parasites often found on grape vines	TNG	"All Good Things"
Legarans	Species who live within a deep layer of mud	TNG	"Sarek"
Lemur	Small primate which Picard began to de-evolve into	TNG	"Genesis"
Lenarians	Species who are not fond of the Federation	TNG	"Tapestry"
Lethean	Humanoid species who can attack others telepathically	DS9	"The Sword Of Kahless"
Leyrons	Species who use gestures for non-verbal communication	TNG	"Loud As A Whisper"
Ligonians	Humanoid civilisation native to Ligon II, who prize honor greatly	TNG	"Code Of Honor"
Ligorian Mastodon	Large but stealthy animal	DS9	"Blaze Of Glory"
Lissepians	Spacefaring civilisation	DS9	"The Maquis, Parts I & II"
Loon	Bird native to Earth	DS9	"Blaze Of Glory"
L-S VI Life-form	Entity discovered by Dr. Mora Pol	DS9	"The Alternate"
Lurians	Humanoid civilisation with two stomachs and multiple hearts. Morn is a Lurian	DS9	"Who Mourns For Morn?"
Lyaarans	Humanoid species who had a cultural exchange with the Federation	TNG	"Liaisons"
Lycosa Tarantula	Spider; Miles O'Brien had a Lycosa Tarantula for a pet	TNG	"Realm Of Fear"
Lynars	Batlike creature which lives on Celtris III	TNG	"Chain Of Command, Part I"
Lytasians	Civilisation who once warred with the Ferengi	DS9	"The Magnificent Ferengi"
M-113 Creature	Creature which needed regular doses of salt to live and was able to project false images of itself	TOS	"The Man Trap"
Macrovirus	Virus which grows up to a metre across and can defy gravity	VOY	"Macrocosm"
Makers	Ancient civilisation which created advanced androids later controlled by Harry Mudd	TOS	"I, Mudd"
Malcorians	Humanoid species which halted its development of warp drive after contact with the Federation	TNG	"First Contact"
Malon	Species which pollutes the galaxy with radioactive waste	VOY	"Night"
Malurians	Civilisation destroyed by Nomad	TOS	"The Changeling"
Manchovites	Civilisation	DS9	"Business As Usual"
Mari	Telepathic civilisation in the Delta Quadrant who have largely eliminated crime	VOY	"Random Thoughts"
Marijne VII Beings	Sentient beings which communicated by directly accessing one anothers thoughts	TNG	"Interface"
Markoffian Sea Lizard	Life form familiar to Q	TNG	"Deja Q"
Mathenites	Civilisation which offered asylum to Legate Ghemor	DS9	"Second Skin"
Mawasi	Delta Quadrant civilisation; in an alternate timeline the Mawasi allied with Voyager against the Krenim	VOY	"Year Of Hell. Part II"
Medusans	Species so ugly that the mere sight of them will drive most beings insane	TOS	"Is There In Truth No Beauty"
Megaptera Novaeangliae	Latin name for the Humpback Whale	Star Trek IV : The Voyage Home
Melkotians	Telepathic species who were strongly isolationist until they encountered Kirk	TOS	"Spectre Of The Gun"
Mellitus	Creature which is solid when still and gaseous when moving	TOS	"Wolf In The Fold"
Memory Virus	Organisms that ate peptides within the hosts brain	VOY	"Flashback"
Menthar	Civilisation which fought the Promellians to their mutual annihilation	TNG	"Booby Trap"
Metron	Highly advanced, long lived civilisation	TOS	"Arena"
Microbiotic Colony	Subatomic life form which eats away at metals	TNG	"A Matter of Honor"
Microbrain	Nonorganic life form native to Velara III	TNG	"Home Soil"
Microvirus	Artificially created organism	TNG	"The Vengeance Factor"
Mikhal Travelers	Delta Quadrant civilisation who are famous for their adventurous lifestyle	VOY	"Darkling"
Mikulaks	Civilisation who donated tissue samples to study Correllium fever	TNG	"Hollow Persuits"
Minnobia	Civilisation at war with the Vek	DS9	"Business As Usual"
Mintakans	Proto-Vulcan species who mistook Picard for a god	TNG	"Who Watches The Watchers?"
Miradorn	Humanoid species composed of symbiotic twins, each sworn to avenge the others death	DS9	"Vortex"
Mizarians	Species who come from Mizar II	TNG	"Allegiance"
Mordian Butterfly	Insectoid life form which resides on Mizar II	DS9	"Profit And Loss"
Moriarty	Sentient holodeck character	TNG	"Elementary, Dear Data"
Moropa	Society hostile to the Bolians	TNG	"Allegiance"
Mugato	White simian creature with a highly poisonous bite	TOS	"A Private Little War"
Muktok Plant	Plant native to Betazed	TNG	"Menage A Troi"
Mylean	Delta Quadrant civilisation similar to Talaxians	VOY	"Scientific Method"
Nagilum	Noncorporeal lifeform which experimented on the Enterprise D crew to determine the nature of death	TNG	"Where Silence Has Lease"
Nanites	Artificial life form created by Wesley Crusher	TNG	"Evolution"
Napean	Humanoid species; partially empathic	TNG	"Eye Of The beholder"
Nasari	Spacefaring species native to the Delta Quadrant	VOY	"Favourite Son"
Nassordin	Delta Quadrant civilisation which traded with the B'omar	VOY	"The Raven"
Nasturtium	Terran plant	TNG	"Imaginary Friend"
Nausicaans	Large Humanoids noted for their aggressiveness and lack of subtlety	TNG	"Samaritan Snare"
Nechani	Civilisation native to the Delta Quadrant	VOY	"Sacred Ground"
Nezu	Civilisation native to the Delta Quadrant	VOY	"Rise"
Night Beings	Delta Quadrant civilisation who lived within the Void and were well adapted to the conditions there	VOY	"Night"
Nihydorn	Delta Quadrant civilisation; in an alternate timeline the Nihydron allied with Voyager against the Krenim	VOY	"Year Of Hell. Part II"
Nitrium Metal Parasites	Spaceborne lifeform which eats metals and converts it into a viscous liquid	TNG	"Cost Of Living"
Norpin Falcon	Bird from the planet Norpin known for its excellent reflexes	DS9	"Sons And Daughters"
Nucleogenic Cloud Being	Life form measuring over a billion kilometres in diameter	VOY	"The Cloud"
Numiri	Civilisation native to the Delta Quadrant	VOY	"Ex Post facto"
Nyberrite Alliance	Spacefaring civilisation	DS9	"The Way Of The Warrior"
Nyrians	Delta Quadrant civilisation who stole starships by replacing their crews one at a time	VOY	"Displaced"
Ocampa	Civilisation native to the Delta Quadrant who have an average lifespan of nine years	VOY	"Caretaker"
Old Ones	Civilisation which used to inhabit Exo III but are now extinct, leaving only their androids behind	TOS	"What Are Little Girls Made Of?"
Old Ones	Leaders of a species which attempted to invade the Federation	TOS	"Catspaw"
Onaya	Noncorporeal species which thrive on the energy of creativity	DS9	"The Muse"
Ophidian	Serpentine creature capable of opening rifts in time	TNG	Times Arrow, Parts I & II
Organians	Noncorporeal species of great power who are horrified by violence	TOS	"Errand Of Mercy"
Orillian Lung Maggot	Form of life native to the Orillian homeworld	VOY	"Fair trade"
Orion Wing-slug	Animal life form	TNG	"Menage A Troi"
Orions	Powerful species of Humanoids. Orion slave women were once sold as slaves	TOS	"The Cage"
Ornarans	Species native to Ornara who were all addicted to Felicium	TNG	"Symbiosis"
Oysters	Terran sea creature considered an aphrodisiac by some	DS9	"His Way"
Pah-wraiths	Noncorporeal beings apparently originating on Bajor; opponents of the Prophets	DS9	"The Assignment"
Pakleds	Humanoid civilisation not known for the intellect	TNG	"Samaritan Snare"
Paradas	Humanoids from the Parada system	DS9	"Whispers"
Parein	Humanoid civilisation composed of former Borg drones	VOY	"Unity"
Paxans	Highly isolationist species who refuse to allow any knowledge of themselves to be known by outsiders	TNG	"Clues"
Peljenite	Species invited to join the Federation in 2371	DS9	"Family Business"
Petarian	Spacefaring civilisation	DS9	"Family Business"
Photonic being	Noncorporeal being found to reside in a protostar	VOY	"Heroes And Demons"
Platonians	Humanoids that once lived on Earth, now possessed of great telekinetic powers	TOS	"Plato's Stepchildren"
Portal	Last living subject of the T'Kon Empire	TNG	"The Last Outpost"
Preservers	Ancient civilisation who transplanted members of primitive peoples to distant planets	TOS	"The Paradise Syndrome"
Progenitors	Ancient civilisation who seeded genetic codes on many worlds	TNG	"The Chase"
Promellians	Civilisation which fought the Menthar to their mutual annihilation	TNG	"Booby Trap"
Providers	Disembodied brains who organised gladiatorial contests on Triskelion	TOS	"The Gamesters Of Triskelion"
Proxcinians	Civilisation at war as of 2373	DS9	"Business As Usual"
Prytt	Humanoids native to the planet Kesprytt II	TNG	"Attached"
Psi 2000 Virus	Water-based virus which behaves in the body like alcohol	TOS	"The Naked Time"
Pygmy Marmoset	Small Earth primate that Data thought Picard might de-evolve into	TNG	"Genesis"
Pygorians	Interstellar traders	DS9	"The Maquis, Part I"
Q	Proper and species name for any of a group of nearly omnipotent transdimensional beings	TNG	"Encounter At Farpoint"
Quantum Singularity Life Form	Sentient species which incubates its young in a black hole	TNG	"Timescape"
Quasi-energy Microbes	Life forms found within a plasma streamer	TNG	"Realm Of Fear"
Rafalian Mouse	Small rodent which Odo enjoyed mimicking	DS9	"Crossfire"
Rakhari	Natives of the planet Rakhar	DS9	"Vortex"
Rakonian Swamp Rat	Unpleasant animal. Kira thought Quark had some similarities to this creature	DS9	"Hippocratic Oath"
Ramurans	Species who went to extreme lengths to prevent contact with outsiders	VOY	"Unforgettable"
Rectillian Vulture	Avian life form native to the Delta Quadrant	VOY	"Phage"
Rectyne Monopod	Creature which can weigh up to two tons	TNG	"The Icarus Factor"
Redjac	Noncorporeal being who feeds on negative emotions, which it provokes by savage murder	TOS	"Wolf In The Fold"
Reegrunion	Humanoid species	DS9	"Sanctuary"
Reeta-hawk	Avian life form from the planet Argratha	DS9	"Hard Time"
Regalian Fleaspider	Arachnid which can be used to create medicine to improve circulation	DS9	"The Ship"
Regulan Blood Worm	Soft shapeless creature which some Klingons think similar in appearance to Kirk	TOS	"The Trouble With Tribbles"
Reptohumanoid Hatchling	Infant creature found on a Delta Quadrant planet	VOY	"Parturition"
Rigelians	Species similar to Vulcans	TOS	"Journey To Babel"
Romulans	Major species with a long history of hostility toward the Federation and Klingons	TOS	"Balance Of Terror"
Rukani	Delta Quadrant civilisation who featured in a holodeck training program created by Tuvok	VOY	"Wost Case Scenario"
Rutians	Humanoids from the planet Rutia IV	TNG	"The High Ground"
Sakari	Humanoid species native to the Delta Quadrant	VOY	"Blood Fever"
Saltah'na	Gamma Quadrant species; they produced telepathic objects which could affect the minds of others	DS9	"Dramatis Personae"
Samarian Coral Fish	Aquatic lifeform which are sometimes perceived in nebula clouds	TNG	"Imaginary Friend"
Sand Bats	Creatures which appear to be inanimate rock crystals, until they attack	TOS	"The Empath"
Sark, Klingon	Riding animal	TNG	"Pen Pals"
Satarrans	Humanoids who have considerable abilities to manipulate minds, but poor weapons technology	TNG	"Conundrum"
Scalosians	Humanoid civilisation who live at a hyperaccelerated rate	TOS	"Wink Of An Eye"
Scathos	Species who kill any woman under forty who conceives a child	VOY	"Elogium"
Sehlat	Vulcan animal resembling a Teddy Bear, but with six inch fangs	TOS	"Journey To Babel"
Selay	Reptilian species native to the Beta Renna system	TNG	"Lonely Among Us"
Seltan Carnosaur	Reptilian lifeform approximately 300 metres tall	DS9	"One Little Ship"
Sheliak	Mysterious and powerful species who signed a complex treaty with the Federation	TNG	"The Ensigns Of Command"
Sikarians	Species which are able to transport instantly up to 40,000 light years from their homeworld	VOY	"Prime Factors"
Sinoraptor	Life form	DS9	"The Darkness And The Light"
Skrreea	Civilisation from the Gamma Quadrant	DS9	"Sanctuary"
Solanagen-based entites	Life forms which reside in a deep subspace domain	TNG	"Schisms"
Son'a	Spacefaring civilisation; an offshoot of the Ba'ku	Star Trek : Insurrection
Soong-type Android	Form of Android based around a positronic network	TNG	"Datalore"
Spawn Beetle	Insect	VOY	"Elogium"
Species 116	Species which resisted assimilation by the Borg for thousands of years before finally succumbing	VOY	"Hope And Fear"
Species 149	Species assimilated by the Borg; the assimilation gave the Borg advanced medical technology	VOY	"Mortal Coil"
Species 259	Borg designation for a species which resided in Galactic cluster 3	VOY	"The Gift"
Species 262	A primitive species assimilated by the Borg around 2145; the Borg gained some knowledge of the Omega molecule from this species	VOY	"The Omega Directive"
Species 263	Species assimilated by the Borg; the species believed the Omega molecule was a drop of their creators blood	VOY	"The Omega Directive"
Species 5174	Borg designation for a Delta Quadrant civilisation	VOY	"Hunters"
Species 8472	Immensely powerful species from Fluidic space who are virtually immune to conventional technologies	VOY	"Scorpion"
Spores, Omicron Ceti III	Symbiotic organism which protect their host from Berthold rays	TOS	"This Side Of Paradise"
Squid	Terran water dweller	DS9	"Blaze Of Glory"
Squill	Plant from the planet Balancar	DS9	"The Magnificent Ferengi"
Swarm	Delta Quadrant civilisation who are highly protective of their territory	VOY	"The Swarm"
Tagrans	Natives of Tagra IV	TNG	"True Q"
Tak Tak	Humanoid Delta Quadrant species obsessed by etiquette	VOY	"Macrocosm"
Takarans	Humanoids who have a disseminated physiology	TNG	"Suspicians"
Takarians	Bronze age civilisation	VOY	"False Profits"
Talarian Hook Spider	Arachnid with legs half a metre long	TNG	"Realm Of Fear"
Talarians	Warrior species with a long history of attacking the Federation	TNG	"Heart Of Glory"
Talavians	Civilisation	DS9	"Things Past"
Talaxians	Delta Quadrant civilisation; Borg designation Species 218	VOY	"Caretaker"
Talosians	Humanoids with powerful telepathic abilities	TOS	"The Cage"
Tamarians	Humanoid species which communicates entirely by metaphor	TNG	"Darmok"
Tanugans	Species native to Tanuga IV	TNG	"A Matter Of Perspective"
Tarchee Cat	Species indigenous to Nechani homeworld	VOY	"Sacred Ground"
Tarellians	Species all but wiped out by biological weapons	TNG	"Haven"
Taresians	Delta Quadrant civilisation	VOY	"Favourite Son"
Targ	Klingon animal sometimes kept as a pet	TNG	"Where No One has Gone Before"
Targhee Moonbeast	Life form noted for its loud call	TNG	"The Perfect Mate"
Tarkalean Condor	Large bird	DS9	"Nor The Battle To The Strong"
Tarkalean Hawk	Predatory bird	DS9	"The Begotten"
Tarkannans	Civilisation	VOY	"Innocence"
Tarkassian Razorbeast	Animal. Guinan had a Tarkassian Razorbeast as an imaginary friend	TNG	"Imaginary Friend"
Tavnians	Humanoids who believe the genders should be separate	DS9	"The Muse"
Tellarites	Humanoids who somewhat resemble Terran pigs	TOS	"Journey To Babel"
Terellians	Four limbed species	TNG	"Liaisons"
Terrellians	Civilisations	DS9	"Life Support"
Thasians	Noncorporeal life form native to Thasus	TOS	"Charlie X"
Tholians	Sentient creatures who are less than friendly to outsiders	TOS	"The Tholian Web"
Tiberian Bats	Avian life form known for staying together	Star Trek VI : The Undiscovered Country
Tiger	Large Terran feline	TOS	"Shore Leave"
Tika Cat	Small animal not known for its bravery	VOY	"Faces"
T'Lani	Humanoid civilisation, at war with the Kellerun until recently	DS9	"Armageddon Game"
Torga	Animal native to the planet Gaia	DS9	"Children Of Time"
Tosk	Species bred to act as prey for the Hunters	DS9	"Captive Pursuit"
Traveler	Native of Tau Alpha C who manipulates time and space with his thoughts	TNG	"Where No One has Gone Before"
Trayken Beast	Large and powerful alien life form	VOY	"Hunters"
Trelane	Member of a powerful species similar to the Q	TOS	"The Squire Of Gothos"
Trellan Crocodile	Large animal known for its strength and destructiveness	DS9	"Crossfire"
Trianic Energy Beings	Trianic energy beings who lived in a dark matter nebula	VOY	"Cathexis"
Tribble	Small furry creatures famed for their prodigious reproduction	TOS	"The Trouble With Tribbles"
Trill	Species composed of a Humanoid Host and a Symbiont	TNG	"The Host"
Trill Host	Humanoid civilisation who are capable of carrying Trill Symbionts	TNG	"The Host"
Trill Symbiont	Small sluglike creature which is capable of joining its personality with a Humanoid host	DS9	"Equilibrium"
Troglytes	One of the groups living on Ardana	TOS	"The Cloud Minders"
T-Rogorans	Gamma Quadrant species	DS9	"Sanctuary"
Troi, Ian Andrew	Life form which impregnated Troi in order to live as a Human	TNG	"The Child"
Troyians	Humanoids native to Troyius	TOS	"Elaan Of Troyius"
Tsetse Fly	Insect	TNG	"Ship In A Bottle"
T'stayan	Talarian riding animal	TNG	"Suddenly Human"
Tube Grubs	Ferengi animal	DS9	"The Jem'Hadar"
Two-Dimensional Creatures	Species encountered by the Enterprise-D	TNG	"The Loss"
Two-Headed Malgorian	Life form famed for its indecision	DS9	"Progress"
Tzenkethi	Alpha Quadrant Species	DS9	"The Adversary"
Ullians	Telepathic Humanoid species	TNG	"Violations"
Vakol Fish	Delta Quadrant life form	VOY	"State Of Flux"
Valerians	Species which sold Dolamide to the Cardassians	DS9	"Dramatis Personae"
Valtese	Species native to the Vault Minor system	TNG	"The Perfect Mate"
Vaskans	Delta Quadrant civilisation who were attacked by the Kyrians while Voyager was passing by	VOY	"Living Witness"
Vek	Civilisation	DS9	"Business As Usual"
Verillians	Species which bought weapons off Quark	DS9	"Business As Usual"
V'Ger	Powerful machine lifeform based on the NASA probe Voyager 6	Star Trek : The Motion picture
Vians	Mysterious species which tested others to determine their worth	TOS	"The Empath"
Vicarian Razorback	Animal noted for its viciousness	DS9	"The Die Is Cast"
Vidiians	Species inflicted with the Phage	VOY	"Phage"
Vok'sha	Civilisation from Rakella Prime	VOY	"Heroes And Demons"
Vorgons	Humanoid species; two Vorgon criminals attempted to steal the Tox'Utat	TNG	"Captain's Holiday"
Vori	Delta Quadrant civilisation who kidnapped offworlders and brainwashed them into fighting in their war with the Kradin	VOY	"Nemesis"
Vorian Pterodactyl	Large flying animal	DS9	"The Ascent"
Vorta	Species enhanced by the Dominion to become political representatives	DS9	"The Search, Parts I & II"
Voth	Humanoid ife form descended from Terran dinosaurs	VOY	"Distant Origin"
Vulcans	Major Alpha Quadrant power. Borg designation Species 3259	TOS	"Amok Time"
Wadi	Gamma Quadrant species fond of games of chance and skill	DS9	"Move Along Home"
Wanoni Tracehound	Predator noted for its persistence	DS9	"The Forsaken"
Wentlian Condor Snake	Life form known as a delicacy	DS9	"Business As Usual"
White Rhinos	Terran animal	TNG	"New Ground"
Wise ones	Another name for the Preservers	TOS	"The Paradise Syndrome"
Wogneer Creatures	Species saved by Picard	TNG	"Allegiance"
Wompat	Rodent native to Cardassia	TNG	"Chain Of Command, Part II"
Xenon based life form	Life form whose chemistry is based on the element xenon	VOY	"Hope And Fear"
Xepolites	Humanoids	DS9	"The Maquis, Part I"
Yaderans	Species of sentient holograms	DS9	"Shadowplay"
Yak Bear	Large animal native to the planet Gaia	DS9	"Children Of Time"
Yallitians	Species native to the Delta Quadrant	VOY	"Phage"
Yalosians	Sentient life forms	DS9	"Improbable Cause"
Yangs	Humanoids native to Omega IV; enemies of the Khoms	TOS	"The Omega Glory"
Yattho	Beta Quadrant civilisation	VOY	"Before And After"
Yridian Yak	Grazing animal known for its size	DS9	"Accession"
Yridians	Humanoid civilisation known as information dealers	TNG	"Birthright, Parts I & II"
Zahl	Delta Quadrant civilisation eradicated by the Krenim in an alternate timeline	VOY	"Year Of Hell, Part I"
Zakdorn	Humanoid species known as great strategic minds	TNG	"Peak Performance"
Zaldans	Humanoids who have webbed fingers and an intense dislike of courtesy	TNG	"Coming Of Age"
Zalkonians	Humanoid species which have begun to evolve into a noncorporeal state	TNG	"Transfigurations"
Zan Periculi	Species native to the Ferengi planet Lappa IV	TNG	"Megage A Troi"
Zetarians	Life energy composed of the inhabitants of Zetar	TOS	"The Lights Of Zetar"
Zevians	Civilisation who requested some information on a smuggling ring from DS9	DS9	"His Way"
Zibalians	Humanoid civilisation noted for facial tattooing	TNG	"The Most Toys"
Zylo Eggs	Life form which Data attempted to paint to test his creativity	TNG	"11001001"