DEFINITIONS OF SYSTEMATIC NAMES. 
Marsupialia, subclass of mammals with 
pouch for young, opossums, kangaroos, 
etc. 
Megalops, genus of fishes including the tar 
pon. : 
Melanerpeton, genus of extinct stegocephal 
amphibians. 
Monodelphia, subclass of mammals, in- 
cluding all except monotremes and 
marsupials. 
Monotremata, subclass of mammals with 
cloaca; includes duckbill and Echidna 
of Australia. ; 
Morones, genus of catfishes. 
Mugil, genus of fishes, mullets. 
Mustelus, genus of small sharks; dogfish. 
Myrmecobius, genus of Australian mar- 
supials. 
Myxine, genus of cyclostomes; hag fishes. 
sa a “group of Cylostomes; hag 
shes. 
Necturus, genus of aquatic amphibians 
with tail and external gills, central U. S. 
Dotidanids, sub-order of sharks with more 
than five gill clefts. 
Nototrema, genus of South American toads 
with dorsal brood sac. 
Ophidia, sub-order of reptiles; snakes. 
Opisthocomus, South American bird, type 
of a separate sub-order. 
Opisthodelphys, genus of tropical American 
tree-toads. : 
Ornithorhynchus, genus of monotremes; 
duckbill of Australia, 
Ostariophysi, bony fishes with Weberian 
apparatus, 
Ostracoderms, a group of extinct verte- 
brates of very uncertain position. 
Paleohatteria, a fossil reptile allied to 
Sphenodon, 
Palzospondylus, a problematical fossil 
vertebrate from Scotland. 
Perennibranchs, ‘tailed amphibia which 
retain the gills through life. 
Perissodactyls, sub order of mammals with 
odd number of toes; horses, rhinoceros, 
tapirs. 
Petrobates, genus of extinct theromorph 
reptiles. 
Petromyzonts, subclass of cyclostomes, 
lampreys. 
Phoca, genus of carnivores including com- 
mon seals, 
Physoclisti, fishes in which the air-bladder 
is closed. 
Physostomi, group of fishes in which the air- 
bladder has a duct; mostly fresh water. 
Pipa, tongueless toad from South America. 
Pisces, the class of fishes. 
383 
Placentalia, all mammals (except marsupials 
and monotremes) in which a placenta 
occurs. ; 
Placodus, genus of extinct. theriomorph 
reptiles 
Plesiosaurs, order of extinct, long-necked 
swimming reptiles 
Polyodon, genus of ganoid fishes, paddle 
fish. 
Polypterus, genus of ganoids from Africa. 
Porichthys, genus of fishes from Pacific; 
midshipman. 
Primates, highest order of mammals, 
including monkeys, apes and man. 
Pristiurus, genus of European dogfish. 
Proboscidea, order of mammals, including 
elephants. 
Procolophon, genus of extinct theromorph 
reptiles. 
Proteus, genus of tailed amphibians from 
caves of Austria, allied to Necturus. 
Protopterus, genus of dipnoi from Africa. 
Psittacus, genus of parrots. 
Pterodactyls, extinct flying reptiles. 
Pterosaurs, extinct flying reptiles, ptero- 
dactyls, 
Pythonomorphs, a group of extinct swim- 
ming reptiles. 
Raia, genus of elasmobranchs, including 
the skates. 
Rana, genus of amphibia, frogs. 
Ratite, birds without keel to sternum, 
ostriches. 
Rhea, three-toed South American, ostrich. 
Rhynchobatus, genus of tropical skates. 
Rhynchocephalia, order of lizard-like rep- 
tiles; Sphenodon of New Zealand only 
living species. 
Rodentia, order of mammals with gnawing 
teeth, rats, rabbits, beaver. 
Ruminants, group of ungulate mammals 
which chew the cud. 
Salamandra, genus of tailed amphibia from 
Europe. 
Salamandrina, order of tailed amphibians 
without gills. 
Salmonids, family of fishes including trout 
and salmon. 
Sauropsida, class of vertebrates including 
reptiles and birds. 
Sceleporus, genus of lizards of eastern 
United States. 
Scomber, genus of fishes; mackerel. 
Scorpenichthys, genus of sculpins. 
Selachii, order of elasmobranchs; sharks. 
Serranide, family of marine, perch-like 
fishes. 
Siluroids, order of fishes containing the 
cat-fishes, 
Siren, genus of tailed amphibian from U.S. 
with external gills. 
