1904.] 



OSTEOLOGY OF CLUPEOIB FISHES. 



479 



The parasphenoifl has no ascending processes in the region of 

 the pro-otics, but there is a well-mai-ked process of each pro-otic, 

 directed foi'ward and downward, whicli is sutiii-ally united with 

 the supei-o-lateral edge of the parasplienoid. The parasjihenoid is 

 short, and undei-lies but a small portion of the basioccipital. It 

 has no posteiior wings, and the eye-muscle canal does not open 

 beliind, although there is a minute depi-ession at the back of the 

 parasphenoid, in the region where the opening might be expected 

 to occur. The anterioi- part of the parasphenoid is broad, 

 V-shaped in section, and united by elaborate jagged sutures with 

 the prefrontals and vomer. The vomer has five or six teeth on 

 each side, the two patches being widely separated. The mesethmoid 

 projects considerably in advance of the vomer and has a doi'sal 

 crest ; yet the ethmoid region as a whole is short. 



Running across the roof of each frontal is an arched bar of 

 bone. The alisphenoids face forwards, i. e. they lie transversely 

 to the cranial axis instead of sloping forward and inward. The 

 orbitosphenoid is fairly large, and is tubular in its hinder two- 

 thirds. It passes back between and Vjelow the alisphenoids, and 

 comes into extensive relation with the pi'o-otic bones. The 

 tubular part does not lie close up under the median suture of the 

 frontals, but is sepai-ated by a vei-tical fenestrated sheet of the 

 orVjitosphenoid bone. The opisthotic is absent, and there seems 

 to be no basisphenoid. 



Text-fig. 137. 



si 

 pt \ cor 



pop 



wp ^/. 



snt 



d 



Coilia nasus, right side of skull. For explanation of lettering see pj. 493. 



Temporal and Preopercular Series (text-fig. 137). — The post- 

 temporal has but one limb, a long oae, the anterior extremity of 

 which rests on the epiotic prominence. This limb is concealed 

 in text-fig. 137 by the supratemporal. The rest of the bone 



