AiiT.2<i. AN EXTINCT VAKANID LIZARD GILMORE. 7 



tion is grooved on the dorsal and ventral sides by longitudinal sulci. 

 On the dorsal surface forward of the center of the bone the develop- 

 ment of a shallow pit marks the point of articulation with the epip- 

 ter^^goid. Anterior to this cuplike depression the bone rapidly widens, 

 being terminated at the anterior extremity by two projecting 

 articular processes, the larger inner process uniting with the palatine ; 

 the smaller outer process with the ectopterygoid. The thin notchlike 

 border connecting these two processes forms much of the inner and all 

 of the posterior boundaries of the infraorbital vacuity. The right 

 pterygoid has a greatest length of 43 mm. ; greatest width of anterior 

 end, 10 mm. 



The resemblance of this bone to the pterygoid of Varanus salvator 

 (Cat. No. 29408, U.S.N.M.) is very close both in size, proportions, 

 and method of articulation with surrounding elements, the only 

 differences observed being the deeper longitudinal sulcus on the 

 ventral side of the posterior half of the fossil bone and the higher 

 and sharper ridges on both the ventral and dorsal sides of the 

 border leading up to the process that meets the ectopterygoid bone. 

 There is no evidence of pterygoid teeth. 



Palatine. — Both palatine bones, but slightly displaced from their 

 proper position in the palate, are shoAvn in plate 1. Only their 

 dorsal surfaces have been uncovered, but so far as they can be 

 compared they appear very similar to the corresponding bones in 

 the Varanus palate. The wide, flattened posterior end unites with 

 the pterygoid. On the external side, near the middle of the bone, 

 a heavy process extends outward to meet the posterior end of the 

 maxilla. As in Varanus, this process is perforated by a longitudi- 

 nal foramen, which leads into a cavity within the maxilla. A slen- 

 der, pointed projection of this process extends backward along the 

 maxilla, that, when articulated, probably met the ectopterygoid and 

 entirely excluded the maxilla from participation in the formation 

 of the boundary of the pterygoid or infraorbital aperture. Ante- 

 riorly the palatine sends forward a slender tapering process that 

 laps the posterior end of the vomer on the inner side. The for- 

 ward ends of the palatines are in contact on the median line, as 

 shown in plate 1, but I am inclined to the belief that this has been 

 brought about by transverse crushing and that originally they were 

 separated, but probably not so wide apart as in the living Varanus. 

 The character of the dorsal surface appears to indicate that it was 

 in contact with the prefrontal and lachrj^mal bones as in Varavus. 



Vomers. — The vomers are relatively wider transversely than in 

 Varanus and they also differ in having a broader and deeper longi- 

 tudinal depression on the dorsal surface. They appear to have been 

 in contact on the median line throughout the greater part of their 

 3136— 22— Proc.N.M.Vol.60— 44 



