GREGORY: FISH SKULLS 



355 



of its mechanism must be erroneous. At most the upper border of the mouth could be 

 everted slightly. The delicate opercular bones, while peculiar, have not helped to solve 

 the problems of relationship. 



The otolith of Ammodytes tobianus described by Frost (1928a, p. 454), is amygdaloidal 

 and biconvex. It gives no clue to near relationship but serves to emphasize the relative 

 isolation of the group. 



50C 



AmTnodytes americanus 



Fig. 234. Ammodytis 



A. lanceolatus 



19 



