124 FOSSILS THEIR NATURE AND ARRANGEMENT. 



wing-sheaths of insects, and the like, are well-known in- 

 stances of this comparative indestructibility among the 

 invertebrata ; while bony scales and scutes, horns, bones, 

 and teeth are still more familiar examples, perhaps, among 

 the vertebrata. In this way, partly by external form, 

 partly by internal structure, and partly by the great anato- 

 mical law of the co-relation of parts, the palseozoologist is 

 enabled to arrive at determinations more satisfactory, on 

 the whole, than those of the palseophytologist. Species, 

 genera, families, and even whole orders, may be extinct ; 

 but, comparing his organisms with the existing, he finds 

 their nearest affinities, and assigns them their place in the 

 systematic arrangements of the zoologist. For this pur- 

 pose the subjoined scheme is in general sufficient, and its 

 study in this place wall greatly facilitate the reader's com- 

 prehension of w r hat may be subsequently stated respecting 

 the fossils of the different formations : 



SCHEME OF ANIMAL CLASSIFICATION. 



VERTEBRATA, 



Or animals with backbone and bony skeleton, and comprehending 



MAMMALIA, AVES, REPTILIA, and PISCES. 

 I. MAMMALIA, or Sticklers; subdivided into Placental and Aplacental. 



1. PLACENTAL, bringing forth mature young. 

 BIMANA (Two-handed) Man. 



QUADRUMANA (Four-handed) Monkeys, Apes, Lemurs. 

 CHEIROPTERA (Hand-winged) Bats, Vampire-bats, Fox-bats. 

 INSECTIVORA (Insect-eaters) Mole, Shrew, Hedgehog, Banxring. 

 CARNTVORA (Flesh-eaters) Dog, Wolf, Tiger, Lion, Badger, Bear. 

 PINNIPEDIA (Fin-footed) Seals, Walrus. 

 RODENTIA (Gnawers) Hare, Beaver, Rat, Squirrel, Porcupine. 

 EDENTATA (Toothless) Ant-eater, Armadillo, Pangolin, Sloth. 

 RUMINANTIA Cud-chewers) Camel, Llama, Deer, Goat, Sheep, Ox. 

 SOLIDUNGULA (Solid-hoofs) Horse, Ass, Zebra, Quagga. 

 PACHTDERMATA (Thick-skins) Elephant, Hippopotamus, Rhinoceros. 

 CETACEA ( Whales) Whale, Porpoise, Dolphin, Lamantin. 



