epo. pr 



FOSSIL AND RECENT 



soc 



ptf 



ex 



ptc 



5mm 

 Fig. 2. Elops hawaiensis Regan. Neurocranium in posterior view. 



subtemporal fossa. A swelling forming an arc above the subtemporal fossa and 

 beneath the hyomandibular facet indicates the path taken by the horizontal semicircu- 

 lar canal through the pterotic. Anteriorly and posteriorly the semicircular canal 

 descends through the prootic and exoccipital respectively before entering the cranial 

 cavity. Medially the pterotic forms the lateral wall of the post-temporal fossa. 

 The posterior face of the pterotic contacts the epiotic above and the exoccipital 

 below the opening of the post-temporal fossa. The union of the pterotic and 

 exoccipital may only be seen in posterior view if the cap-like intercalar is removed. 



The epiotic is seen in dorsal and posterior views of the neurocranium. From the 

 former aspect it is represented by a knob-like process, protruding posteriorly from 

 beneath the parietal and pterotic. In posterior view the epiotic forms part of the 

 dorsal and medial margin of the opening leading to the post-temporal fossa. 



Between the epiotics lies the supraoccipital which, in posterior view, is pentagonal. 

 The flat surface of the supraoccipital is interrupted only by a weakly defined vertical 

 crest which becomes more prominent dorsally. In dorsal view the supraoccipital 

 is seen as a small triangle, the apex of which lies between the posterior ends of the 

 parietals. Beneath the roof the supraoccipital extends forward as a median and 

 two antero-lateral projections. The latter reach forward to meet the frontal of either 

 side and in so doing form the median walls of the post-temporal fossae. The supra- 

 occipital is pierced by canals which carry the posterior vertical semicircular canal of 

 either side. Laterally, this semicircular canal descends through the epiotic where its 

 passage is visible externally as a ridge along the medial margin of the post-temporal 

 fossa opening. Ventrally, the posterior vertical semicircular canal runs through the 



