486 THE RABBIT CHAP. 



epiderm. Along the ventral surface of the body in the 

 female are four or five pairs of papillae the teats, on 

 which open the ducts of the milk-glands, which corre- 

 spond to modified integumentary glands. The various 

 parts of the skeleton (Fig, 130) can be felt through the 

 skin, and it will be noticed that the anterior part of the 

 trunk, or thorax, is surrounded by ribs, many of which 

 meet below with a breast-bone or sternum, and which are 

 absent in the posterior part of the trunk, or abdomen. 



Beneath the anterior end of the snout is the transverse 

 mouth, which has a narrow gape and is bounded by 

 upper and lower lips : the upper lip is divided by a 

 longitudinal cleft which is continuous with the oblique, 

 slit-like external nostrils. Just inside the lips are the 

 upper and lower front teeth or incisors, which are chisel- - 

 shaped, and behind them the hairy integument is 

 continued on either side into the cavity of the mouth. 

 The eyes are protected by movable hairy upper and lower 

 eyelids, as well as by a hairless third eyelid or nictitating 

 membrane (compare p. 5), supported by cartilage and 

 situated in the anterior corner of the eye, over which it 

 can be partly drawn : it corresponds to the little red 

 lump in the inner corner of the human eye. On the 

 upper lip and above and below the eye are certain very 

 long and stiff hairs the " whiskers " or vibrissce, and 

 behind the eyes are a pair of long and movable external 

 ears or pinna : these are supported by cartilage and are 

 somewhat spout-shaped, leading to the external auditory 

 openings. 



Below the root of the tail is the anus, and in front of 

 and below this the urinogenital aperture, the space 

 between them being known as the perineum. On either 

 side of these apertures is a hairless depression of the skin 

 on which open the ducts of the perineal glands, the 

 secretion of which has a strong and characteristic odour. 



