88 CATALOG OF FOSSIL FISHES IN THE MUSEUM 



mm. 



Length as far as preserved 62 



Length of tritoral margin (concave portion) 40 



Depth at middle of tritoral portion , 12 



E 1963 Front half of a small right mandible of about the same size as 

 the preceding. It shows well the tritoral region and the 

 beak, which is completely preserved. Behind the tri- 

 toral excavation there is, as in the preceding specimen, 

 a compressed tritor, beveled on the outer face. It is 

 straddled at intervals of i or 2 mm. by line-like tritors. 



mm. 



Length of excavated portion of tritor 43 



Length of element as far as preserved 61 



E 1964 A right mandible of about the same size as the co types, 

 lacking the posterior extremity (PI. 23, fig. i). It is 

 embedded in matrix, and shown in outer view. It differs 

 somewhat from the cotypes : the excavated portion of the 

 tritoral area is shorter, and the outer margin of the tri- 

 toral area is a sharp line instead of being rounded out- 

 ward. These features, however, are probably only 

 individual variations. 



mm. 



Length of element as far as preserved 122 



Length of excavated portion of tritoral region 46 



Depth at about middle of functional region 20 



Greatest width of tritor 6 



Behind the excavated portion of the tritoral region 

 there is a short tritor 18 mm. in length. 



E 1966 Front half of a small left mandible, showing well the exca- 

 vated portion of the tritoral region and the beak (PI. 24, 

 fig. 4) . In the symphyseal region there are three or four 

 denticle-like protuberances, rather irregular in outline. 

 The tritoral region behind the excavated portion is not 

 preserved. Total length of element as far as preserved, 

 75 mm.; depth at about middle of functional region, 16. 



E 1967 Front half of a left mandible, smaller than any of the pre- 

 ceding, and rather poorly preserved. The beak is miss- 

 ing, as is also the tritoral region behind the excavated 

 portion of the tritoral margin. 



