NORTH AMERICA AND THEIR VERTEBRATE FAUNA. 



171 



On the posterior face of the bone a ridge starts just above the opening 

 of the foramen and runs obhquely across the bone; becoming sharper and 

 higher toward its distal end, it terminates free from the articular face. The 

 distal articular face is confined entirely to the end of the bone. The face for 

 the ulna is slightly oblique, v^inding around the end of the bone; the radial 

 condyle is hardly distinguishable. 



Length of the bone, 87 mm. Width at upper edge of the entepicondylar 

 process, 49.5 mm. Height of the entepicondylar process, 44.5 mm. 



Pelvis. — There are a number of ilia (No. 3428, fig. 45, a and b) more closely 

 resembling that of Varanosaurus than any other known form from the Texas 

 beds, but as Varanosaurus does not occur in the Wichita, these bones are 

 provisionally associated with Poliosaurus as the most likely form. A perfect 

 specimen of average size has an elongated narrow crest projecting almost 

 directly to the rear. The outer face of the crest is smooth, but on the inner 

 face there is a strong, sharp ridge standing out at right angles to the rest of 

 the bone. The anterior end of this ridge is the highest and it gradually 

 diminishes until it disappears upon the distal portion of the face. The ridge 

 is almost identical with that found in the same position in Varanosaurus and 



Fig. 45. — (o) outer face, (6) inner face of ilium of right side of Poliosaurus (?), No. 3428. 



(c) ilium of right side of unnamed reptile, No. 3429. X %• 



(d) inner face, (e) inner edge of pubis of right side of unnamed reptile, No. 3245. X j4- 



Pcecilospondylus and perhaps is to be regarded as indicating some relationship 

 between the forms mentioned from the upper and lower formations. The 

 similarity to Varanosaurus is also to be seen in the somewhat elongated 

 cotylus, with the face for the ischium longer than that for the pubis, the 

 two faces standing almost at right angles to each other. Length of an 

 average specimen, 58.5 mm. 



It is possible that the pubes referred to Cricotus may belong with this 

 ilium and to Poliosaurus, for they strongly resemble the pubes of Varanosaurus. 



A small ilium, No. 3429 (fig. 45, c), is totally different from the preceding; 

 it may be that of an amphibian, but is more probably reptilian. The crest is 

 somewhat imperfect, being slightly broken at the posterior end. The cotylus 

 is relatively deep. The articular surfaces for the pubis and ischium are deeply 

 hollowed out, showing the presence of a considerable quantity of cartilage and 

 the probable immaturity of the animal. The form is best appreciated from 

 the figure. 



