MORPHOLOGICAL REVISION 



127 



coracoid, since, in the immature specimen already spoken of, a sutural line 

 seems to run directly backward below the upper edge of the preglenoid 

 facet, quite as in Varanosaurus. The lower edge of the preglenoid facet 

 continues as a rounded border downward and forward part way to the 

 lower margin of the bone. In the cavity thus formed at the lower end of 

 the facet is the opening of the supracoracoid foramen. On the inner surface 

 of the bone, near the middle, extending downward subparallel with the 

 anterior border of the bone, is the anterior border of the subscapular fossa. 

 In its middle part the free border overhangs a deep fossa looking backward, 

 at the upper end of which opens the supraglenoid foramen; at the lower end 

 is the opening of the supracoracoid foramen. Back of this margin the bone 

 is convex, and is pierced by the inner opening of the glenoid foramen. 



" Cleithrum: The cleithrum, found in position on either side, is remark- 

 able for its large size. Its lower part is a long rod closely attached to the 

 anterior margin of the scapula as far as the angular thickening I have de- 

 scribed; it is overlapped through nearly its whole extent by the upper part 

 of the clavicle. The upper part of the cleithrum is broadly dilated and thin, 

 covering the upper border of the scapula to its hind angle and arched 

 inward. Its borders are very thin, convex above, concave below; the poste- 

 rior thin margin is nearly straight. The bone above forms a sort of roof 

 convex outwardly, concave inwardly. 



" Clavicles: The clavicles are small, somewhat spoonshaped, with curved 

 handle. The upper, slender part is closely applied to the outer, anterior 

 side of the lower, rodlike part of the cleithrum, reaching nearly to the dilated 

 portion. The lower end, curved inward and a little backward, is dilated 

 with thin margins, concave on the inner side where it articulates with the 

 interclavicle, convex on the exterior or lower surface. It underlaps the 

 interclavicle and partly covers the lower anterior border of the epicoracoid. 



" Interclavicle: The interclavicle is a small, thin bone, dilated and thinned 

 in front, where it overlies the ends of the clavicles, which touch in the middle. 

 The posterior extension or 'stem' is short, not as long as the expanded part. 



"Humerus: The humerus is of the usual temnospondyle form, differing 

 from that of Eryops and Trematops, especially in the absence of the entepi- 

 condylar process, so conspicuous in the former and in Euchirosaurus. It is 

 broadly expanded at either extremity in planes nearly at right angles with 

 each other, and has a rather slender shaft in the middle. The lateral or 

 radial process is very stout; the medial or ulnaf process is indicated by a 

 slight ridge or elevation just below and in front of the inner extremity of 

 the proximal articular surface. The digital fossa on the inner side is rather 

 shallow and broad. The short shaft is subcylindrical in cross-section, with 

 a sharp ridge running from the outer side of the lateral process to terminate 

 in the supinator ridge. The capitular surface for the radius is subhemi- 

 spherical in shape, looking mainly forward. The trochlear surface for the 

 ulna is small. The inner, condylar border is moderately dilated and rela- 

 tively thin; the ectepicondylar or supinator border thick. There is no indi- 

 cation whatever of the ectepicondylar process below the lateral process on 

 the outer side. 



"Radius (plate 23): The radius has a very slender shaft in the middle, 

 and is broadly and thickly expanded at either end. The posterior border 

 is nearly straight, the anterior deeply concave, the two lateral borders 

 nearly symmetrically and deeply concave in outline, the extremities of nearly 



