26 AMPHIBIA AND PISCES OF THE PERMIAN OF NORTH AMERICA 



"The coracoid is but little incurved; its internal border is convex, and 

 is roughened as though for cartilaginous attachment. Its superior portion 

 forms a convex continuum with the scapula. The direct line or external 

 face of the scapula extends in a nearly plane surface to the glenoid cavity, 

 embracing a perforating foramen above the latter, precisely as in the Pelyco- 

 sauria. Its surface is continuous anteriorly with a wide expansion forwards, 

 whose fine, inner border is continuous with that of the coracoid. This plate 

 doubtless includes a third element, but its borders are not preserved, on 

 account of the obliteration of the sutures. It is probably epicoracoid, as 

 in the Pelycosauria. In its form it is less produced than in the known scap- 

 ular arches of the latter. 



"The coossified pelvic elements resemble, in their compression below, 

 the corresponding parts in the Anura. The ilia are, however, shorter and 

 worn as in the Urodela. They are flat and stand at right angles to the line 

 of the ischiopubic symphysis. There is an open concavity of their inferior 

 posterior free border, and a facet-bearing elevation on the inferior border, 

 or that entering into the formation of the acetabulum. The latter is large 

 and half as long again as deep. The anterior and posterior borders of the 

 pelvis descend regularly to the inferior edge, forming with it a triangle. 

 The ischiadic or posterior border is but little thickened; the anterior or 

 pubic is flat in front and presents a reverted edge outwards. This expands 

 prominently where it is joined by a ridge which bounds the acetabulum below; 

 it there contracts to an inferior apex. Beneath the anterior point of the 

 acetabulum it is pierced by the usual foramen, which issues on the inner 

 edge of the anterior face, just above the symphysis. 



"The humeral bones of this genus I probably possess, but I have several 

 forms between which I am not able to decide. They are in general like those 

 of the Pelycosauria, but differ from them in not having an Inclosed supracon- 

 dylar arterial foramen, but only the buttresses of Its inclosing arch. Two 

 such forms I have already described, and a third has been obtained from the 

 French Permian by Professor Gaudry, One quite similar to the latter I have 

 since obtained from Texas. Not having been able at first to determine the 

 proper reference of these humeri, I suggested to Professor Gaudry that his 

 humerus belongs to one of the Pelycosauria, and he accordingly described It as 

 Euchirosaurus rochei. I now think that there is greater reason for believing 

 that it belongs to a species of the same group as Eryops and Actinodon.* 



"In all these humeri the extremities are expanded in different planes, 

 and the shaft contracted. The articular surface of the proximal extremity 

 is band-like and passes obliquely from one side to the other, as in the Pely- 

 cosauria. The condyles are large, consisting of a globular portion and a 

 depressed trochlea without ridges at one side of it. 



"The femora are very different from the humeri, but in much the same 

 way as in the corresponding bones of existing Batrachia. There are no con- 

 dyles at either extremity, but outlines of such, inclosing roughened surfaces. 

 These look as though the bases of attachment of cartilaginous caps or 

 epiphyses. The proximal extremity is convex, and is extended in one direc- 

 tion. One border, the anterior. Is regularly gently convex; the opposite arc 

 is strongly convex near one end only. The articular face is in two planes, 

 one larger than the other. The trochanteric fossa is at first shallow, and 



*Thevinin has recently shown (66) that Euchirosaurus must be regarded as a synonym of Actinodon. 



