NOTES ON THE CORACO-SCAPULA OF ERYOPS COPE. 



OONTEIBUTION PEOM THE PALEONTOLOGIOAL LABORATOEY No. 51. 



BY S. W. WILLISTON. 

 With Plates xxYii, xxix, and xxx. 



APAR,T only of the coraco-scapula of Eryops has hitherto been 

 made known, and figured, by Cope. In a specimen comprising 

 a large ])art of the skeleton, collected by Mr. C N. Gould, from 

 the Red Beds of the Indian territory, near the southern line of 

 Kansas, a nearly complete coraco-scapula has been removed from 

 the matrix, and is figured herewith in plates xxvii and xxix. 



The bone is elongated, and nowhere very thick or massive. The 

 distal part of the scapula is much thinned and considerably ex- 

 panded ; the immediate margin here, however, is wanting, so that the 

 precise outlines cannot be given. 



The position of the two bones must have been very oblique, as is 

 evident from the position of the glenoid cavity. The postero-inferior 

 border is moderately thickened, and rounded ; gently concave along 

 the proximal part and convex distally. The antero-superior border is 

 much thinner than the ojjposite one, and is concave throughout the 

 "Extent of the shaft, except distally, where it is coossified with the 

 procoracoid. The union of these two bones is very close in this 

 region, the sutural line being distinguished with difficulty, if at all. 

 The procoracoid is narrower and more thickened below, reaching to 

 the lower part of the conjoined bone, and lying in close apposition, 

 though not suturally united. Both the lateral surfaces of the scapula 

 are nearly flat. A little proximad to the narrowest part of the shaft 

 the bone is much thickened by a stout ridge on the inner side, which 

 includes between it and the remainder of the bone, just back of or 

 above the cotylus, a large, elongated foramen, both of whose orifices 

 can be seen from the inner side of the bone only. 



The glenoid surface is elongated and deeply concave in its long 

 diameter. The scapular portion is much smaller than the coracoid, 

 and is partly separated from it by a constriction ; this surface is nearly 

 flat and is placed at right angles to the plane of the coracoid surface, 

 looking directly downward when the bone is lying horizontally. The 

 rest of the cotylus is moderately concave and looks outward, and 



1— K.U.Qr. A-viii4 [185]-K.U.Qr.— A viii 4-Oct. '99. 



