SKELETON OF KODENTIA. 



167 



which they support. In most Eodents with long tails, htema- 

 pophyses are developed beneath the intervertebral spaces, as in 

 the Jerboas, fig. 232, h. In one member of the Porcupine family 

 ( Cercolabes), and in one species of Capromys ( C. prehensilis), the 

 tail has a prehensile extremity. 



The seventh cervical vertebra has an imperforate transverse 

 process in some Kodents, a perforate one in others : in the Hare 

 I have observed this difference in different individuals. The 

 pleurapophyses early anchylose to form the vertebrarterial foramen 

 in the sixth-second cer^dcals. The neural spine is usually longest 

 in the second and seventh ; it is obsolete in the intermediate cer- 

 vicals in many Rodents. In the Hare the transverse processes of 

 the atlas are perforated longitudinally by the vertebral arteries, 

 which then perforate the neural arch. The hypapophysis, or 

 so-called body, is ossified, and a small tubercle extends backward 

 from its under part. In the atlas of the Chinchilla the transverse 

 process is pierced both horizontally and obliquely, and the verte- 

 bral artery also perforates the neural arch. 



B. Skull. — As in the Marsupialia, the' confluence of the elements 

 of the epencephalic arch is late, and that of the tympanic is 

 restricted to the petrosal and mastoid. The squamosal maintains 

 its individuality, and also much of its long slender proportions, 

 and the malar is suspended in the middle of the zygomatic arch, 



'283 



Skull of the Hare, 



as in Birds : other characteristics of the Rodent skull will l^p 

 exemplified in the follomng species. 



In the Hare (^Lepus timidus, fig. 233) the superoccipital is 

 surmounted by a square platform of bone — originally a distinct 

 interparietal — the posterior angles of which project backward in the 

 form of two tubercles, from between which a vertical crest descends 

 to the foramen magnum. The paroccipitals arch downward and 



