M 'clung: the KANSAS CRETACEOUS. 239 



tween the elements of the girdle. The hypercoracoid is ex- 

 panded into a broad, thin plate as it disappears under the 

 clavicle. It extends to the ventrocaudal border of the clavicle 

 and dorsally to over half its height. This forms the outer 

 boundary of a long dorsoventral fissure, the entire inner limit 

 of which is fixed by the mesocoracoid. Only above the hyper- 

 coracoid plate does the clavicle border this cleft. Hay ('98, p. 

 43) was in error when he described this fissure as being limited 

 by the outer and inner plates of the clavicle. In the very 

 slightly crushed specimen from which plate X was made the re- 

 lations of the coracoid elements are beautifully shown. The 

 sutures joining these lie immediately back of the articular 

 facets. Between the hyper- and hypocoracoid is a bone that has 

 not heretofore received notice, and I am unable to homologize 

 it with any described element of the girdle. I shall therefore, 

 because of its position, call it the intercoracoid. It is small and 

 wedge-shaped, with the apex directed dorsally against the base 

 of the mesocoracoid and a mesial wing extending ventrally to 

 unite with the hypocoracoid. Its separation from the hyper- 

 coracoid is strongly marked by a heavy suture passing through 

 the fossa where the second baseost is set. A heavy, rounded 

 process arises from the outer dorsal edge of the hypocoracoid 

 and impinges against the ventral, horizontally placed surface 

 of the intercoracoid, just in front of the facet for the articula- 

 tion of the fin-rays. Some of these relations are better seen in 

 a lateral view, and will be referred to later. 



The mesocoracoid rests broadly upon the intercoracoid, and 

 is joined to it by a heavy suture that runs almost horizontally. 

 Above the oval foramen the mesocoracoid sends a broad wing 

 that joins the inner surface of the hypercoracoid at about the 

 level of the outer suture between this bone and the clavicle. 

 The articular facets of the hypercoracoid form an almost 

 straight line, whose angle on inclination is about forty-five de- 

 grees from the median plane of the animal. Upon the caudal 

 margin of the hyper- and intercoracoids, at the level of the 

 interspace between the middle and lower facets, are two fossae 

 for the reception of the T-shaped baseosts. The outer of these 

 lies equally upon the two bones, but the inner and shallower 

 one is entirely confined to the intercoracoid, although its dorsal 

 margin touches the suture uniting this bone to the mesocora- 

 coid. 



An external view of the girdle shows all the elements more 



