Classification of the Mammalia. 59 



ing on fuci, water plants or the grass of the shore. There is much 

 in the organization of this order that indicates its affinity to mem- 

 bers of the succeeding division. 



In the Ungulata the four limbs are present, but that portion of 

 the toe which touches the ground is incased in a hoof, which blunts 

 its sensibility and deprives the foot of prehensile power. With 

 the limbs restricted to support and locomotion, the Ungulata 

 have no clavicles ; the fore-leg remains constantly in the state of 

 pronation, and they feed on vegetables. 



The third division of the Gyrencejphala enjoy a higher degree 

 of the sense of touch through the greater number and mobility of 

 the digits, and the smaller extent to which they are covered by 

 horny matter. This substance forms a single plate, in the shape 

 of a claw or nail, which is applied to only one of the surfaces of 

 the extremity of the digit, leaving the other, usually the lower, 

 surface possessed of its tactile faculty ; whence the name Ungui- 

 culata, applied to this group, however, is more restricted and 

 natural than the group to which Linnaeus extended the term. All 

 the species are ' diphyodont,' and the teeth have a simple invest- 

 ment of enamel. 



The first order, Carnivora, includes the beasts of prey, pro- 

 perly so called. With the exception of a few Seals, the incisors 

 are ^r 3 in number; the canines 7^5 always longer than the other 

 teeth, and usually exhibiting a full and perfect development as 

 lethal weapons ; the molars graduate from a trenchant to a tuber- 

 culate form, in proportion as the diet deviates from one strictly of 

 flesh to one of a more miscellaneous kind; The clavicle is rudi- 

 mental or absent ; the innermost digit is often rudimental or 

 absent; they have no vesiculae seminales; the teats are abdominal 5 

 the placenta is zonular. The Carnivora are divided, according to 

 modifications of the limbs, into ' pinnigrades,' 'plantigrades' and 

 ' digitigrades. ' In the Pi nnigrades (Walrus, Seal-tribe) both fore 

 and hind feet are short, and expanded into broad, webbed paddles 

 for swimming, the hinder ones being fettered by continuation of 

 integument to the tail. In the Plantigrade? (Bear-tribe) the whole 

 or nearly the whole of the hind foot forms a sole, and rests on 

 the ground. In the Digitigrades (Cat-tribe, Dog-tribe, &c.) only 

 the toes touch the ground, the heel being much raised. 



It has been usual to place the Plantigrades at the head of the 

 Carnivora, apparently because the higher order, Quadrumana, is 

 plantigrade ; but the affinities of the Bear, as evidenced by inter- 

 nal structure, e. g. the renal and genital organs, are closer to the 



