MAMMALIA. 



239 



Ord er I V . R UMINA N TIA . 

 The Ruminantia, or the natural Order re- 

 cognized by Aristotle under the name of 

 Mnfvna.^nra, subsequently adopted by all Zoo- 

 logists, have their external and internal cha- 

 racters alike conspicuous and cogent. These, 

 according to Pallas are, incisors wanting in 

 the upper jaw; hoofs bifid; habit of the whole 

 body; stomach quadruple; intestines very long 

 with a coecum ; suet for fat ; cotyledons in place 

 of placenta. The genera included in this order 

 are Camelus, ]\loschus, Cervus, JEgoceros, Bos, 

 Ant Hope. 



Order V. ANOMALOPODA. 



The genera grouped together by Pallas under 

 this name differ, he observes, from each other 

 in their dental apparatus and the structure of 

 their feet, yet nevertheless are linked together 

 by natural affinity (" sed tainen inter se naturali 

 uffinitute coluerent"). Thus Hippopotamus is 

 allied to Equus, the horse to Rhinoceros and 

 its congener Hydroch&rus, and these to the 

 genus Sus. The following characters are com- 

 mon to the whole order: niolares truncate, tritu- 

 rating; feet ungulate, supported on the digits; 

 stomach a macerator, with enormous colon and 

 caecum ; clavicles wanting; produce perfect; 

 food vegetable. 



The genera which Pallas exemplifies in this 

 Order, which corresponds with the Pachyderma 

 of Cuvier (the Proboscidians being excepted), 

 are Equus, Sus, Rhinoceros, Hippopotamus. 



Order VI. BELLVJE. 



In this Order, characterized by incisors 

 none; canines projecting from the upper jaw 

 only, composed of ivory ; molars few, mamma 

 pectoral (in which the Belluse mainly differ 

 from the Anomalopoda) ; feet, with connate 

 digits forming a shapeless sole; Pallas in- 

 cludes the genera Etephas and Rosmarus, re- 

 jecting therefrom the Trichecus or Manatee, 

 as having the hind-feet coalescing with the tail, 

 and therefore more rightly to be referred to the 

 Cetaceous Order. In this latter view Cuvier 

 agrees with Pallas. As to the rest it is scarcely 

 necessary to say that the tusks of the Elephant 

 differ from those of the Walrus in being im- 

 planted in the inter-maxillary bones instead of 

 the maxillaries, and are therefore regarded as 

 incisors. 



Order VI I. CETACEA. 

 Pallas observes that since the Cetacea differ 

 from the other Lactantia chiefly in having 

 their boneless posterior extremities blended 

 with the cartilaginous tail (" quod artus posticos 

 exosses, in caudam cartilaginibus fultam co- 

 adunatos obtinent"), the Manatus and Trichechus 

 rightly fall under this Order, although they ap- 

 proach more to the nature of Quadrupeds. 

 Both the Manatus proper and the Rytina, 

 which is the Manatus Borealis of Pallas, agree, 

 however, with the true Cetacea in having no 

 other rudiments of posterior extremities than 

 some small pelvic bones. 



We shall now proceed to the arrangement 



of the Mammalia proposed by Cuvier in the 

 last edition (1829) of the ' Regne Animal;' 

 and this is the more interesting, as, in giving 

 the outline of his method, he developes the 

 principles on which the divisions of the class 

 are founded. 



" The characters by which Mammalia differ 

 most essentially one from another are derived 

 from the organs of touch, from which results 

 their degree of dexterity, and from the organs 

 of mastication, which determine the nature of 

 their food ; and, as a corollary to these, de- 

 pends not only every thing which is connected 

 with the digestive functions, but a variety of 

 other circumstances relative even to their de- 

 grees of intelligence. 



" The perfection of the organs of touch is 

 estimated by the number and mobility of the 

 digits, and the extent to which they are inclosed 

 in a claw or in a hoof. A hoof which com- 

 pletely incloses that part of the digit which 

 touches the ground, precludes the exercise of 

 it as an organ of touch or of prehension. The 

 opposite extreme is where the nail, in the form 

 of a simple lamina, covers only one side of the 

 end of the digit, leaving the other side in pos- 

 session of all its delicacy of tact. 



" The kind of food is indicated by the 

 molar teeth, to the form of which the arti- 

 culation of the jaws invariably corresponds. 



" For cutting flesh, the molar teeth must be 

 trenchant and serrated ; and the jaws fitted to- 

 gether, so as to move like the blades of a pair of 

 scissors, simply opening and closing in the 

 vertical direction. 



" For bruising grains and roots, the molar 

 teeth must have flattened crowns, and the jaws 

 a horizontal motion : and further, that the grind- 

 ing surface may be always unequal, like a 

 millstone, the teeth must be composed of sub- 

 stances of different degrees of density, and con- 

 sequently wearing down in different proportions. 



" The ungulate quadrupeds are all of neces- 

 sity herbivorous, or with flat-crowned molars 

 (fig. 59), because the conformation of their feet 

 does not permit them to seize living prey. 



Pig. 59. 



Lower jaw, African Elephant. 



" The unguiculate animals are susceptible of 

 more variety. They are not limited to one kind 

 of food ; and, besides the consequent variation 

 in the form of their molars, they differ ma- 

 terially from each other in the mobility and 

 sensibility of their digits. There is, more- 

 over, a characteristic which prodigiously in- 



