1909.] 



OLFACTORY ORGAN OF TELEOSTEAN FISHES. 



631 



the mouth is opened and closed is peculiar. When the lower jaw 

 is depressed by the action of the gular muscles the premaxilla is 

 strongly protruded by the forward pressure of a hooked process of 

 the coronoid border of the mandible (text-fig. 200, B, c') upon the 

 hinder margin of the premaxilla. By this movement of the pre- 

 maxilla the membranes between it and the palatine are stretched 



Text-fig. 200. 



AnahJeps microlepis. 



A. Position of the nostrils. 



B. The nasal cavity in its relation to the neighbouring bones of the face. 



C, hooked process on the coronoid border of the mandible that 

 protrudes the premaxilla. 



and the nasal sac distended . Closure of the jaws by the contraction 

 of retractor muscles inserted upon the premaxilla and the coronoid 

 process of the mandible is accompanied by a retraction ot the pre- 

 maxilla and the compression of the nasal sac. In this mechanism 



