Stewart.] Cretaceous Fishes, 275 



metapterygoid is a broad, Hat plate just above the quadrate, 

 and is covered with Hue striae on the lower portion. 



The symplectic is a rather small element, occupying a groove 

 on the inner side of the quadrate. On its superior end it pre- 

 sents a small articular facet. 



The quadrate is very thin above where it joins the metaptery- 

 goid, but in passing downward to the condyle it becomes more 

 robust and is contracted into a neck. The condyle is somewhat 

 elliptical in outline, the ellipse being invaded by a deep notch 

 on the external side, and is strongly convex from before back- 

 ward. On the internal side there is a deep groove for the sym- 

 plectic, and just back of this groove, posteriorly, there is another 

 smaller groove into which the anterior border of the preoper- 

 culum fits. The anterior border articulates with the pterygoid 

 by means of a squamose suture. The bone is minutely striated, 

 both externally and internally. 



Greatest length of arch 342 mm. 



Anterior depth of malleolar body -tO " 



Between malleolar body and condyle for the quadrate 261 " 



Anteroposterior length of palatine 298 " 



Depth at center of the arch 131 " 



The opercular bones are represented by the operculum, pre- 

 operculum, and a supposed suboperculum. There is still another 

 bone (plate XLIII, fig. 3), which may represent an interoper- 

 culum. 



The operculum is a broad, flat plate of bone, near the anterior 

 superior portion of which there is a deep elliptical pit for articu- 

 lating the bone with the hyomandibular. This pit is projected 

 slightly outward from the rest of the bone, very closely resembling 

 tlio corresponding portion of Saurodon in this respect. Just above 

 this pit there is a sharp angular projection at the point where 

 tli*' anterior and superior borders meet, but I am inclined to 

 think that this character will not be constant in all specimens. 

 From this point the superior border extends backward and down- 

 ward in an irregularly curved line to the lower border, which 

 is less curved and somewhat striated just above it. The ante- 

 rior border, extending from the articular portion just mentioned 

 downward, is nearly straight and somewhat thickened. Back 



