XXvi THE MAMMALS OF INDIA. 



III. IsoDONTiA. — Teeth when present of one kind and often 



very numerous. 

 Ord. Cetacea. — Post-extremities wanting. 



B. IMPLACENTAL OR MARSUPIAL MAMMALS. 



In the body of the work the orders do not follow exactly as in this 

 synopsis. I have made the Insectivora follow the BatSj and the 

 Cetacea the Carnivora. 



This classification is nearly that of Cuvier, but he classed Bats, 

 Insectivora and Carnivora, in one group, Carnaeia, and placed the 

 8irenia with the true Cetacea. 



The following is the classification adopted by Linnaeus. 



I. Unguiculata. — With nails. 

 Ord. Primates. — Monkeys and Bats. 

 „ Fercc. — Insectivora and Carnivora. 

 ,, Glires. — Are Rodentia. 

 ,, Briita. — The Ant-eaters, Elephant, and PJiinoceros. 



II. Ungulata. — Hoofed. 

 Ord. Pecora. — Ruminantia. 

 „ Bellua. — Pachydermata, except the order Bruta above. 



III. Mutica. — Wanting the posterior extremities, Cetacea. 



This, it will be seen, is, with the exception of his separating the 

 Elephant and Rhinoceros from the other Pachydermata, essentially 

 the same as Cuvier's, and the system adopted here. 



Professor Owen classifies Mammals according to the .structure of 

 the brain alone, and, excluding Man, whom he places by himself, as 

 the type of his Archencephala, he divides the Mammal class into three 

 great groups — Lyencephala, LissencepJiala, and Gyrencephala. The 

 first comprises the Implacental or Marsupial animals, and is quite 

 natural. In this group the olfactory lobes, part of the optic lobes, as 

 well as the cerebellum, are all exposed, and the lobes of the cerebrum 

 are not connected by a corpus callosum. 



The Lissencephala, or smooth-brained Mammals, have the corpus 

 callosum, but the cerebrum is smooth in most and of small bulk. 

 This group is composed of the Cheiroptera, Insectivora, Bodentia, and 



