FOSSIL AND RECENT 



vo fapmx 



129 



pto 



boc 



/ 

 X 



exo 



ic 



Fig. 62. Pterothrissus gissu Hilgendorf. Neurocranium in ventral view. 



bulla. At two points the prootic fails to meet the basioccipital : anteriorly where 

 these bones meet the parasphenoid and posteriorly where they meet the exoccipital. 

 There are thus left two triangular interspaces, which even in the largest specimen 

 examined remain open. 



A large foramen for the hyomandibular trunk of VII opens directly from the pars 

 jugularis, so that when the neurocranium is viewed laterally (Text-fig. 61) the tri- 

 geminal and facial foramina may be seen opening from the pars ganglionaris. The 

 orbital artery enters the prootic at the base of a deep groove situated immediately 

 above the ascending wing of the parasphenoid. The orbital face of the prootic is of 



