TO MAiMUALS. XIU 



The previous remarks (page x) will have prepared the reader 

 for the first step in the arrangement of Mammals, viz., their divi- 

 sion into those in which the young are nourished in the maternal 

 uterus by means of a placenta, — Placental MammalSj — and those in 

 which the young foetus is expelled at a very early period, and main- 

 tained in a pouch firmly attached to a nipple, Imi-lacental, or 

 Marsupial animals. None of these last occur in the Asiatic pro- 

 vince, being chiefly developed in the Australian region, and a few in 

 America. They have, moreover, very anomalous forms of dentition. 



Having separated the Marsupial animals, the great mass of the 

 Mammals still remains. Taking the teeth as our guide, we find a 

 large number of animals possessed of all four kinds of teeth {vide 

 page iv) though in varying number and proportion. These are called 

 by Blyth, Tkpodontia, i. e., animals with the typical forms of teeth 

 developed, and include Man,* Monkeys, Bats, Carnivorous animals 

 and Shrews, &c., in fact all the most perfect forms of Mammals. 

 We next find a large and still more varied association of animals, of 

 inferior and more specialized organization, in which the teeth vary 

 much from the typical formation, and have rarely more than two 

 kinds of teeth developed. This gi-oup is called by Blyth, Diplodon- 

 TiA, and includes Rats and S{j[uirrels, Deer, Sheep and Cattle, the 

 Elephant, Pig and Horse, and the almost toothless Ant-eaters. 

 They chiefly live on vegetable matter, as the majority of the Typo- 

 dontia do on animal food. 



A third small division, comprising the Whales and Porpoises, 

 &c., were called Isodontia by Blyth, because the teeth when present 

 are all of one kind. 



Having thus divided Placental Mammals into three great groups, 

 which can in most cases be recognized by a glance at the teeth, 

 the next step is to divide them into orders ; and first the typically 

 toothed Mammals. On examining the hairy covering of a Monkey 

 and a Bat, it will be seen that there is only one kind of hair, no 

 underhair or wool being present. In both these animals too, the 

 penis is pendent, and not sheathed as in all other animals. As 

 Man belongs to this division, it was called Pmmates by Linnaeus. 



• Man is excluded from the scope of the present work. 



