TO MAIIJIALS. XV 



Sheep, &c. They have two hoofs, and two upper supplemental 

 ones, no upper incisors (except in the Camel) and flattened molars. 

 A canine is present in a few. 



The Pachydermata is a more varied and artificial group than 

 the Ruminants, comprising the Elephant, Rhinoceros, Hippo- 

 potamus, Pig, Horse and Tapir. They differ much in their denti- 

 tion and only agree in the negative character of not ruminating, 

 and perhaps it would be more scientific to divide them into sepa- ' 

 rate orders as some have done, viz., CHa5R,0DiA for the Hippopo- 

 tamus and Pig ; Pboboscidea for the Elephant ; and Belluba for 

 the others. 



The herbivorous Cetaceans, sometimes classed with Pachyder- 

 mata, are generally separated as a distinct order, called Sieenia, and 

 are distinguished from the other Diplodonts by the absence of limbs. 



The IsoDONTiA, comprising the Whales, Dolphins and Porpoises, 

 are generally called Cetacea, and have no posterior extremities, 

 whilst their anterior limbs are changed into fins. 



Such is the Classification adopted in the present work, of which 

 the accompanying synopsis may be found useful. 



A. PLACENTAL MAMMALS. 

 (Foetus nourished in the uterus through a placenta.) 



I. Typodontia. — Teeth of all four kinds. 

 1st Group, Primates. — Hair of one kind only. 

 Ord. Quadrumana. — With thumb on the feet. 

 „ Cheiroptera. — Winged. 



2nd Group, Secundates. — Hair of two kinds. 

 Ord. Car^ivora. — Molars trenchant mixed with tubercular ones. 

 „ Insectivora. — Molars studded with cusps. 



II. DiFLODONTiA. — Teeth generally of two kinds only, abnormal. 

 Ord. Rodentia. — Pront teeth long and chisel-like. 

 „ Pachydermata.— T!QQ\h varied— skin thick— do not ruminate. 

 Ruminantia, — Upper incisors generally absent — chew the 



cud. 



Sirenia. — Want posterior extremities, 

 %. — Inciisors absent. 



