PERMO-CARBONIFEROUS VERTEBRATES FROM NEW MEXICO. 



19 



the quadrates are inclined backward and inward ; the lower ends of the quadrates 

 and the temporal or tabulare bones reach as far back, nearly, as the occipital condyle. 



Resemblances to Diadectes lentus: The basisphenoid is broad and short 

 instead of narrow and elongate as in Animasaurus ; the articular faces of the quad- 

 rates are broad antero-posteriorly ; in Animasaurus they are narrow. 



In this specimen no trace can be found of the palatine processes of the max- 

 illaries so characteristic of the family, but as the skull is poorly preserved and 

 has been badly crushed it seems to us more probable that the processes have been 

 injured beyond recognition than that they were absent. 



The lower jaw: On the right side the articular portion is missing, but on the left 

 side it is the posterior portion of the jaw which is preserved, so that the length and 

 proportions of the jaws can be made out. It 

 was less deep than in Diadectes, but in other 

 respects very similar. There was a well- 

 defined coronoid process and the usual two 

 Meckelian openings on the inner side, the an- 

 terior one seemingly somewhat smaller than 

 in Diadectes. The anterior end of the two 

 jaws, in position, was narrower, correspond- 

 ing to the narrowed muzzle. The broken 

 condition of the specimen reveals the deep 

 sockets of the incisor teeth and the roots of 

 several teeth marked by the deep linear 

 grooves due to the folding of the dentine. 

 The articular surface of the articular bone 

 shows two deep concave faces, which, in op- 

 position to the corresponding prominences 

 on the lower face of the quadrate, limited 

 the motion of the jaws to a strictly verti- 

 cal plane. As in the skull, the outlines of 

 the individual bones can not be made out. 



The shoulder-girdle: This, as is not uncommon in the specimens of the family, 

 is well preserved and almost undistorted ; this is due to its strength, the close artic- 

 idation of the bones, and probably also to the presence of a considerable quantity 

 of tough cartilage. The distal half of the right scapula, portions of the cleithra, 

 and the tip of the posterior end of the interclavicle are wanting. In comparison 

 with the scapula of Diadectes, the blade is shorter and the proximal portion wider. 

 The posterior edge is more sharply curved, forming a semicircle. The lower, or 

 inner, edge is straight in the middle, curving gently at the posterior end to join 

 the posterior edge of the bone and more sharply at the anterior end to join the 

 anterior edge. The anterior edge is nearly straight, with scarcely noticeable faces 

 for the clavicle and cleithrum. The posterior edge is crescentic in outline, becom- 

 ing more sharply curved toward the proximal end. On the outer face there is a 

 prominent preglenoid tuberosity anterior to and above the humeral cotylus; pos- 

 terior to it the edge of the bone is broad and bifurcates to include the supraglenoid 

 fossa with, apparently, a supraglenoid foramen at its bottom. On the other, ante- 

 rior, side of the tuberosity is a deep and wide opening, which terminates at the 

 bottom in the supracoracoid foramen. Just beneath the preglenoid tuberosity and 

 anterior to the articular surface is a very large, funnel-like foramen, the glenoid, 

 which is the largest foramen observed by us in this position in any of the cotylo- 

 saurs. The articular surface has the usual two facets, the upper, anterior, facing 



F1G.8.- 



Diasparactus zenos Case, X %. Restora- 

 tion of lower surface of skull. 



