In the 10th edition of Systema Naturae (published 1758–1759), Carl Linnaeus described the Mammalia as one of the six classes of animals, characterized by being:
Animals that suckle their young by means of lactiferous teats. In external and internal structure they resemble man: most of them are quadrupeds; and with man, their natural enemy, inhabit the surface of the Earth. The largest, though fewest in number, inhabit the ocean.
Linnaean Characteristics
Heart: 2 auricles, 2 ventricles. Warm, dark red bloodLungs: respires alternatelyJaw: incombent, covered. Teeth usually withinTeats: lactiferousOrgans of Sense: tongue, nostrils, eyes, ears, & papillae of the skinCovering: hair, which is scanty in warm climates, hardly any on aquaticsSupports: 4 feet, except in aquatics; and in most a tail. Walks on the Earth & SpeaksLinnaeus divided the mammals based upon the number, situation, and structure of their teeth.
Fore-teeth: cutting, upper 4 parallel, (except in some species of bats which have 2 or none)Tusks: solitary, that is, one on each side, in each jawTeats: 2 pectoralFeet: 2 are handsNails: (usually) flattened, ovalFood: fruits, except a few who use animal foodHomo (humans)Homo sapiens – human Homo troglodytes – partly based on myth, partly on orangutans Simia (monkeys & apes) Simia satyrus – Bornean orangutan & common chimpanzeeSimia sylvanus – Barbary macaqueSimia sphinx – mandrillSimia apedia – nomen dubiumSimia silenus – lion-tailed macaqueSimia faunus & Simia diana – Diana monkeySimia paniscus – red-faced spider monkeySimia cephus – moustached guenonSimia aygula – nomen oblitum for the crab-eating macaqueSimia hamadryas – hamadryas baboonSimia jacchus – common marmosetSimia oedipus – cottontop tamarinSimia aethiops – grivetSimia midas – red-handed tamarinSimia cynamolgus – possibly crab-eating macaqueSimia apella – tufted capuchinSimia morta – nomen dubiumSimia capucina – white-headed capuchinSimia sciurea – common squirrel monkeySimia syrichta – Philippine tarsierLemur (lemurs & colugos) Lemur tardigradus – red slender lorisLemur catta – ring-tailed lemurLemur volans – Philippine flying lemurVespertilio (bats)Vespertilio vampyrus – large flying foxVespertilio spectrum – spectral vampire batVespertilio perspicillatus – Seba's short-tailed batVespertilio spasma – lesser false vampire batVespertilio leporinus – greater bulldog batVespertilio auritus – brown long-eared batVespertilio murinus – parti-coloured batFore-teeth: none in any jawTusks: in elephants and manateesFeet: with strong hoof-like nailsMotion: slowFood: (mostly) masticated vegetablesElephas (elephants)Elephas maximus – Asian elephantTrichechus (manatees)Trichechus manatus – West Indian manateeBradypus (sloths)Bradypus tridactylus – pale-throated slothBradypus didactylus – Linnaeus's two-toed slothMyrmecophaga (anteaters)Myrmecophaga didactyla – silky anteaterMyrmecophaga tridactyla – giant anteaterMyrmecophaga tetradactyla – southern tamanduaManis (pangolins)Manis pentadactyla – Chinese pangolinFore-teeth: conic, usually 6 in each jawTusks: longerGrinders: with conic projectionsFeet: with clawsClaws: subulateFood: carcasses and preying on other animalsPhoca (seals)Phoca ursina – northern fur sealPhoca leonina – southern elephant sealPhoca rosmarus – walrusPhoca vitulina – harbour sealCanis (dogs & hyenas)Canis familiaris – domesticated dog Canis lupus – grey wolfCanis hyaena – striped hyenaCanis vulpes & Canis alopex – red foxCanis lagopus – Arctic foxCanis aureus – golden jackalFelis (cats)Felis leo – lionFelis tigris – tigerFelis pardus – leopardFelis onca – jaguarFelis pardalis – ocelotFelis catus – domesticated cat Felis lynx – Eurasian lynxViverra (mongooses, civets, and skunks)Viverra ichneumon – Egyptian mongooseViverra mephitis – striped skunkViverra putorius – eastern spotted skunk Viverra zibetha – large Indian civetViverra genetta – common genetMustela (weasels & kin)Mustela lutris – sea otterMustela lutra – European otterMustela gulo – wolverineMustela barbara – tayraMustela martes – European pine martenMustela putorius – European polecatMustela furo – ferret Mustela zibellina – sableMustela erminea – stoatUrsus (bears)Ursus arctos – brown bearUrsus luscus – wolverineUrsus meles – European badgerUrsus lotor – northern raccoonFore-teeth: indefinite numbers on the sides, always have one extra canineNose: elongate, used to digFood: digs out juicy roots and verminSus (pigs)Sus scrofa – wild boar & domesticated pigSus porcus – red river hogSus tajacu – collared peccarySus babyrusa – Buru babirusaDasypus (armadillos)Dasypus unicinctus – southern naked-tailed armadilloDasypus tricinctus & Dasypus quadricinctus – Brazilian three-banded armadillo Dasypus sexcinctus – six-banded armadilloDasypus septemcinctus – seven-banded armadilloDasypus novemcinctus – nine-banded armadilloErinaceus (hedgehogs)Erinaceus europaeus – European hedgehogTalpa (moles)Talpa europaea – European moleTalpa asiatica – Cape golden moleSorex (shrews)Sorex araneus – common shrewSorex cristatus – star-nosed moleSorex aquaticus – eastern moleDidelphis (opossums)Didelphis marsupialis – common opossumDidelphis philander – bare-tailed woolly opossumDidelphis opossum – grey four-eyed opossumDidelphis murina & Didelphis dorsigera – Linnaeus's mouse opossum Fore-teeth: cutting, 2 in each jawTusks: noneFeet: with claws formed for running and boundingFood: bark, roots, vegetables, etc., which they gnawRhinoceros (rhinoceroses)Rhinoceros unicornis – Indian rhinocerosRhinoceros bicornis – black rhinocerosHystrix (porcupines)Hystrix cristata – crested porcupineHystrix prehensilis – Brazilian porcupineHystrix dorsata – North American porcupineHystrix macroura – Asiatic brush-tailed porcupineHystrix brachyura – Malayan porcupineLepus (rabbits & hares)Lepus timidus – mountain hareLepus cuniculus – European rabbitLepus capensis – Cape hareLepus brasiliensis – Brazilian rabbitCastor (beavers)Castor fiber – European beaverCastor moschatus – Russian desmanMus (mice & kin)Mus porcellus – domestic guinea pig Mus leporinus – red-rumped agouti Mus lemmus – Norway lemmingMus marmota – Alpine marmotMus monax – groundhogMus cricetus – European hamsterMus amphibius & Mus terrestris – European water voleMus rattus – black ratMus musculus – house mouseMus avellanarius – hazel dormouseMus sylvaticus – wood mouseMus striatus – typical striped grass mouseMus longipes - midday jird Mus jaculus – lesser Egyptian jerboaMus volans – southern flying squirrel Sciurus (squirrels)Sciurus vulgaris – red squirrelSciurus niger – fox squirrelSciurus cinereus – Delmarva fox squirrelSciurus flavus – [nomen dubium] Sciurus getulus – Barbary ground squirrelSciurus striatus – eastern chipmunkSciurus volans – Siberian flying squirrel Fore-teeth: no upper, lower cutting, manyFeet: hoofed, clovenFood: herbs which they pluck, chews the cudStomach: 4:the
paunch to macerate and ruminate the foodthe
bonnet, reticulate, to receive it,the
omasus, or maniplies of numerous folds to digest it,and the
abomasus', or caille, fasciate, to give it acescency and prevent putrefaction
Camelus (camels)Camelus dromedarius – dromedary camelCamelus bactrianus – domestic Bactrian camel Camelus glama – domestic llama Camelus pacos – domestic alpaca Moschus (musk deer)Moschus moschiferus – Siberian musk deerCervus (deer & giraffes)Cervus camelopardalis – giraffeCervus alces – elkCervus elaphus – red deerCervus tarandus – reindeerCervus dama – fallow deerCervus bezoarticus – pampas deerCervus capreolus – roe deerCervus guineensis – [nomen dubium] Capra (goats & antelope)Capra hircus, Capra depressa, Capra reversa, & Capra mambrica – domestic goat Capra ibex – Alpine ibexCapra rupicapra – chamoisCapra pygmea – royal antelopeCapra gazella – gemsbokCapra cervicapra – blackbuckCapra dorcas – dorcas gazelleCapra grimmia – common duikerCapra ammon – argaliOvis (sheep)Ovis aries, Ovis guineensis, & Ovis strepsiceros – domestic sheep Bos (cattle)Bos taurus – domestic cattle Bos bonasus – wisentBos bison – American bisonBos bubalis – domestic water buffalo Bos indicus – zebu Fore-teeth: obtuseFeet: hoofedMotion: heavyFood: gathering vegetablesEquus (horses)Equus caballus – domestic horse Equus asinus – donkey Equus zebra – mountain zebraHippopotamus (hippopotamuses)Hippopotamus amphibius – hippopotamusHippopotamus terrestris – South American tapirFins: pectoral instead of feetTail: horizontal, flattenedClaws: noneHair: noneTeeth: in some cartilaginous, in some bonyNostrils: none, instead of which is a fistulous opening in the anterior and upper part of the headFood: mollusca & fishHabitation: the oceanMonodon (narwhals)Monodon monoceros – narwhalBalaena (baleen whales)Balaena mysticetus – bowhead whaleBalaena physalus & Balaena boops – fin whale Balaena musculus – blue whalePhyseter (sperm whales)Physeter catodon, Physeter macrocephalus, Physeter miscrops & Physeter tursio – sperm whale Delphinus (dolphins & porpoises)Delphinus phocaena – harbour porpoiseDelphinus delphis – short-beaked common dolphinDelphinus orca – orca 
