GREGORY: FISH SKULLS 



347 



ordinary specializations of the goby type of skull. The very large orbits are lifted above 

 the rest of the skull and the eyes are erectile (Tate Regan, 1911c, p. 733). The quadrate- 

 articular joint is moved forward in front of the anterior orbital rim; the jaws are of a modi- 



FiG. 227. Unidentified Goby from Bahamas. 



fied nipping type with remarkably stout protrusile premaxillae, reduced maxillae and inter- 

 locking maxillary processes of the palatines. 



The hyomandibular is remarkably wide anteroposteriorly; on the lower end of this 

 bone the preopercular appears as an almost vestigial patch. The interopercular forms the 

 tracker that is characteristic of advanced derivatives of the percomorph stock. The bran- 

 chial chamber is small and with it the opercular and subopercular. The use of the pectoral 



Periophthalmus 



Fig. 228. Periophthalmus. 



