545 



border, then sloping abruptly downward to the relatively low, 

 squarely truncate occipital region. Ventral profile not parallel 

 with dorsal profile, scarcely curved. Brain-case . not differen- 



FlG. 107. 

 Hystrix cristata. x I. 



tiated as an evident region, its width greater anteriorly than 

 posteriorly, the entire surface of each parietal occupied by a 

 cleop depression for muscular attachment, the posterior margins 



2 N 



