PHYLUM CHORDATA 



433 



extremity the mouth, in the form of a transverse slit bounded by 

 soft lips. The upper lip is divided by a longitudinal cleft, running 

 backwards to the nostrils, and exposing the chisel-shaped incisor 

 teeth. Behind the incisor teeth the hairy integument projects on 

 each side into the cavity of the mouth. At the end of the snout, 

 above the mouth, are the nostrils, in the shape of two oblique slits. 

 The large eyes, situated at the sides of the head, have each three 

 eyelids, an upper and a lower hairy lid, and an anterior hairless 

 third eyelid or nictitating membrane, supported by a plate of cartilage. 

 Vibrissce very long stiff hairs are scattered above and below the 

 eyes and on the snout. Behind the eyes, and a little nearer the 

 summit of the head, are a pair of very long flexible and movable 

 external ears or pinnce. These are somewhat spout-shaped, 

 expanding distally, and are usually placed vertically with the 

 concavity directed laterally and somewhat forwards, leading to the 





FIG. 1091. Lepus cuniculus. Lateral view of skeleton with outline of body. 



external auditory opening. The neck is a distinct constriction, but 

 relatively short as compared with the neck of the Pigeon. The 

 trunk is distinguishable into thorax in front and abdomen behind. 

 On the ventral surface of the abdomen in the female are four or five 

 pairs of little papillse the teats. At its posterior end, below the 

 root of the tail, is the anal opening, and in front of this in the male 

 is the penis, with a small terminal urinogenital aperture, and with 

 the testes, each in a prominent scrotal sac, at the sides ; and in the 

 female the opening of the vulva. In the space (perinceum) between 

 anus and penis or vulva are two bare, depressed areas of skin into 

 which open the ducts of certain glands the perinceal glands with 

 a secretion having a strong and characteristic odour. The tail is 

 very short and covered with a tuft of fluffy fur. 



The fore- and hind-limbs, both of which take part in locomotion 

 and in supporting the weight of the animal, differ considerably in 

 size the fore-limbs being much shorter than the hind-limbs. 

 Both have the same general divisions as in the Lizard. The upper 



