GREGORY: FISH SKULLS 



147 



very small and bounded above only by the premaxilla, the small maxilla being excluded 

 from the gape. The forwardly-produced suspensorium ends in front of the lower border 

 of the orbit and the mandible is directed sharply upward. 



5cak hone 



smx 



come 



Chatoessus erebi 



Fig. 39. Chatoessus erebi. After Ridewood. 



In Engraulis (Fig. 40), on the other hand, the suspensorium is directed obliquely 

 backward, the quadrate-articular joint being well behind the orbit; the jaws are long and 

 slender but wholly below the round protruding snout. In Dussumieria, with forwardly- 

 inclined suspensorium and short jaws, the cranium as seen from above is excessively narrow, 

 with very large orbits. In Coilia (Fig. 41), with backwardly-inclined suspensorium and 

 long jaws, the maxilla is produced backward far behind the skull inco a long, narrow 

 denticulate rod, the orbits are small and the cranium very broad between the orbits. 

 According to Ridewood (1904i, p. 478) the hyomandibular has no articulation with the 

 pterotic but only with the sphenotic, — a most unusual arrangement. 



The family heritage beneath this diversity is especially well revealed in the detailed 

 characters of the cranium (Fig. 38^). A few of the outstanding cranial characters recorded 

 by Ridewood (1904a, b) are as follows: (1) in this family the primitive posttemporal 

 fenestrse of the Elopidae are lacking, or represented by a large groove between the epiotic 

 and the pterotic ("squamosal"); (2) there are caecal diverticula of the swim-bladder con- 



