SKIN AND MUSCLES. 659 



eye is bathed by the water, and it is rudimentary in man 

 and monkeys where its absence is compensated for by the 

 habitual winking of the upper eyelid. The nostrils are two 

 slits at the end of the snout, and are connected with the 

 mouth by a " hare lip " cleft in the middle of the upper lip. 

 In front of the mouth are seen the chisel-edged incisors, a 

 pair on the mandibles, and two pairs on the premaxillje, — 

 the smaller pair hidden behind the larger pair. The first 

 milk incisors above and below never cut the gum, but are 

 absorbed before birth ; the second milk incisors above 

 (there are none below) are functional, but are shed about 

 the third week of extra-uterine life ; the same is true of 

 the milk premolars. Into the toothless gap or diastema 

 between the front and back teeth, the hairy skin of the lips 

 projects into the mouth. On the sides of the snout, and 

 about the eyes, there are tactile hairs or vibrissa. 



The plump trunk is separated from the head by a 

 short neck. The tail is very short, but in the scampering 

 wild rabbit it is conspicuous as a white tuft, which some 

 naturalists interpret as a directive signal. Beneath the base 

 of the tail the food canal ends, and beside the anus are the 

 openings of the perineal glands, whose secretion has a charac- 

 teristic odour. In front of the anus is the urinogenital 

 aperture, — in the male at the end of an ensheathed penis, 

 in the female a slit or vulva, with an anterior process or 

 clitoris — the homologue of the penis. Beside the penis in 

 the male lie the scrotal sacs, into which the testes descend 

 when the rabbit becomes sexually mature. Along the 

 ventral surface of the thorax and abdomen in the female 

 there are four or five pairs of small teats or mammae. 



The limbs have clawed digits, five on the fore feet, four 

 on the hind feet ; they are very hairy. 



Skin and Muscles. 



The skin is thickly covered with hair, and has the usual 

 sebaceous and sudorific glands, besides special glands, such 

 as the perineal glands beside the anus, the glands of the 

 eyelids, the lachrymal glands, and the mammary glands 

 developed in the females. Between the skin and the 

 subjacent muscles there is a layer of fatty tissue, known as 

 the panniculus adiposus ; it is present in all Mammals 



