496 Edward Phelps Àllis jr., TlieLateio-Seiisory Canals and Related Bones in Fishes. 



The point uf oiigin of the supratemporal canal from the main 

 infraorbital canal is very variable in its relations to the sense organs 

 of the latter line. This is particularly true of the Chondropterygii. 

 In the Teleostei, Ganoidei Holo>tei and Crossopterygii it apparently 

 has a constant position, but even here there may or may not be an 

 ante-commissural, postfacial sense organ which, when found, is usually 

 enclosed in the hind end of the squamosal. In the bony fishes the 

 canal is almost invariably enclosed in an independent extrascapular 

 bone or bones. In Cottus and in certain of the Ostariophysi it is 

 partly enclosed in the parietal; but there is here quite certainly a 

 fusion of parietal and extrascapular elements. 



The dermal postfrontal bone encloses, and develops in relation to 

 the dorsal postorbital sense organ of the main infraorbital line. It 

 is a purely dermal bone and must in no way be confused with that 

 primary ossification of the post orbital process of the skull that 

 is variously known as the postfrontal, auto-postfrontal, and sphenotic. 



Palais Carnolès, Menton, April 11*^, 1904. 



