110 



antero-posterior portion. From its middle upward, it supports the zijgomatic. 

 The latter has no great extent anteriorly to its malar suture ; and its inferior 

 margin arches high above the line of the condyles of the quadrate. 



^\i& pterygoid bones are subtriangular in outline, with concave sides, an 

 emarginate base, and a very obliquely truncate apex, which articulates low 

 down on the quadrate bone. Both margins are thickened and rounded ; the 

 superior as a boundary of the foramen ovale. The posterior margin of the 

 platelike columella overlaps it on the inner side, deeply notching it ; on the 

 outer side, the suture is zigzag and transverse. The superior part of the 

 bone is produced like a flat rod, and, at its end, exhibits a squamosal suture 

 for union with what is, in the snapper, a postero-inferior rod-like prolongation 

 of the columella. No such process of the columella appears to exist in this 

 species. The columellar plate is half as large as the pterygoid, and exhibits 

 the obUque suture in front for the descending lamina of the parietal. 



The postfrontal hone of the left side is preserved entire, and the inferior 

 portion of that of the right. The inferior margin for the malar is the longest, 

 and is straight. The orbit is excavated in part from its anterior margin ; 

 while the supero-posterior is a continuous curve. The inferior suture is a 

 groove, whose inner bounding wall is convex, but rises past the straight outer 

 to an inner ridge, which probably approaches the ectopterygoid region. 

 A large sutural face for the zygomatic exists at the lower posterior angle, and 

 an elongate one above for the parietal. The inner face is concave, indicating 

 a large temporal fossa, as in Sphargis and Chelone. 



Two bones, of opposite sides of the cranium, are either those portions 



of the pterygoids which bound the temporal fossa below in front, or those 



portions of the maxillary bounding the palatine foramen. As the free margin 



is much thickened, they are probably the former. Their inner, or thinner, 



lamina is marked for squamosal suture with other bones, perhaps columella 



and palatine. 



Measurements of the cranium. 



M. 



Depth of the preniaxillary sutnro of the maxillary 0. 060 



Length from the premaxillary suture to the iuner nares 0.008 



Depth of the maxillary below tho orbit 0.035 



Depth of thedentary at the symphysis 0.078 



Depth of tho notch of the deutary at the symphysis 0.044 



Depth of the dentary behind the symphysis 0.09,5 



Depth of the deutary at the coroiioid region 0. 085 



Depth of the ramus at the front of the cotylus U.OGl 



Length of the pterygoid fossa of the cotylus 0. OGO 



