REPTILIA : CASEA 125 



great development of the coracoid part, and the relative slenderness 

 of the upper, scapular part, which is preserved complete on one 

 side. This part is moderately thick, convex internally, concave 

 externally. The front border, for about twenty millimeters, is 

 thickened and rounded, that part above the extremity of the clav- 

 icle. Below this the border is thin, and for the most part is lost 

 in both scapulae. The glenoid articulation is large and well formed, 

 that on the preglenoid facet looking downward, backward, and 

 outward; that on the metacoracoid looking more directly outward 

 and a little backward. The supracoracoid foramen is, as usual, a 

 little below and in front of the margin of the preglenoid facet, 

 I find no supraglenoid foramen, either in the supraglenoid fossa, 

 which is very shallow, or on the outer side in front, as in Dimetrodon 

 and Varanosaurus. The very large coracoid turns inward hori- 

 zontally and is a little concave longitudinally. Sutures between 

 the coracoid elements, or between them and the scapula, are not 

 distinguishable, but, in all probability, that separating the meta- 

 coracoid, which, unlike the condition in Varanosaurus, is well 

 ossified, passes directly inward at about the middle part of the 

 fossa. The fossa on the inner side, into which opens the supra- 

 coracoid foramen, is rather short. Just back of the metacoracoid 

 facet on the upper border of the bone there is a rather prominent 

 process corresponding with the more prominent one in the same 

 place in Dimetrodon. Possibly its presence is indicative of genetic 

 affinity, since it is absent in other known scapulae. 



Humerus (Plate XX, Figs. 1-3). — The humerus, while in general 

 resembling that of Varanosaurus, presents several marked differ- 

 ences, distinguishing the two forms immediately. The planes of 

 the extremities are almost at right angles to each other; the slender 

 shaft of the bone, as seen from the front, is distinctly above the 

 middle; the entepicondylar foramen is larger, and is not situated 

 so close to the inner margin; the ectepicondylar process is broader 

 and more protuberant, and the entocondylar dilatation is produced 

 more inward in a direct line, and is thickened. The lateral process 

 is much stouter and projects more inward; the capitellum forms 

 almost a hemisphere, the chord of its convexity looking forward 

 at an angle of about forty-five degrees, and its articular surface 



