1904. 



OSTEOLOGY OF CLIJPEOID FISHES. 



485 



The third limb of the post-tenijjoral is wanting, since the supra- 

 temporal overlaps the body of the post-temporal. The supra- 

 temporal is a flat scale of bone, with the usual trii-adiate sensoiy 

 canal near its lower edge. It covers in the space between the 

 epiotic limb of the post-tempoiul above and the squamosal s})ine 

 below. 



Text-%. 141. 



pnv 



moc 



d 



hop 



anp 



sop pop 



Chanos salmoneus, right side of skull. For explanation of lettering see p. 493. 



Overlapping the antero-superior })art of the opercular Ijone is ji. 

 flat bone which may be termed the " subtemporal." A branch of 

 the sensory canal passes from the supi'atemporal down the 

 anteiior edge of the bone on its way to the preopei'culai', which 

 fact, taken in conjunction with the position of the bone below the 

 squamosal and above the pi'eopei'culai-, points to the conclusion 

 that the bone is the homologue of that which, in the Salmon, 

 Parker (Phil. Trans. Roy. Soc. clxiii. 1873, p. 99 and pi. 6. 

 fig. 1, st) erroneously called the supratemporal. 



In relation with the forward displacement of the quadrate 

 articulation, the interopercular and the lower limb of the pre- 

 opercular are much elongated in a horizontal direction. 



Circumorhital Series (text-fig. 141). — There are eight bones of 

 this series. The orbital ring is complete, there being two elongated 

 supi'aorbitals which meet above the eye. The anterioi' of the two 

 is in the large specimens examined (A and C) swollen after the 

 manner of the frontal and some other bones of E])hvppus. The 

 nasal is I'emarkably small and liable to be overlooked. 



Maxillary Series (text-fig. 141). — The premaxilla and maxilla 

 are short and broad, the gape being greatly reduced in size. 

 Except when the mouth is opened to an unnaturally wide extent, 

 the premaxilla alone bounds the gape above. Both the premaxilla 

 and maxilla are thin, curved scales with sharp lo-i^er edges, devoid 

 of teeth. There is no sur maxilla. 



