m'clung: the Kansas cretaceous. 243 



The articulation of the fin-rays with the girdle has been cor- 

 rectly described, in its general features, by Stewart ('00, p. 

 284), but a few details may be added. In figure 7 are shown 

 the proximal ends of the fin-rays, and upon them, in dotted out- 

 line, the largest baseost. The fainter dotted outlines within 

 represent the articular facets which are applied to the lower, 

 two of the hypercoracoid. The deep depression in the proximal 

 end of the first dorsal fin-ray abuts against the upper facet of 

 the hypercoracoid. Upon the opposite side of the large baseost 

 are a number of articular surfaces for contact with the ventral 

 fin-rays. Just under the proximal ventral facet (a of figure 7) 

 is a large flattened surface which articulates with a similar 

 area upon the proximal end of the first ventral fin-ray. At the 

 opposite extremity is an elongate, irregular facet which affords 

 contact with the second, third, and possibly fourth, ventral 

 raj^s through their facets c, d and e. The exact position in the 

 fin apparatus of the two T-shaped baseosts is not exactly de- 

 terminable, but their proximal ends are set in the two deep de- 

 pressions of the hypercoracoid and intercoracoid. The distal 

 ends, with their broad articular surfaces, undoubtedly bore 

 upon the proximal ends of the fin-rays. 



The relative positions of the various bones may be seen from 

 an inspection of plate XII, which is from a photograph of the 

 restoration in the University of Kansas. 



PECTORAL GIRDLE OF GILLICUS. 



Several fine specimens in the museum of the University of 

 Kansas make it possible to give a fairly complete picture of the 

 pectoral girdle of Gillicus. One is at once struck with the gen- 

 eral resemblance this bears to the corresponding structure in 

 Xijjhactimis. Such differences as there are may be referred 

 very. largely to variations in proportions. An examination of 

 figure 8 will give a general idea of the lateral aspect of the 

 girdle. Here it will be seen that the ventral limb of the clavicle 

 is much larger in proportion than it is in Xvphactinus. The 

 dorsal limb is of the same general form, but no supraclavicle 

 was found. In all probability it was present, however, for an 

 articular surface similar to that of Xiphactinus is evident. The 

 hypocoracoid also is larger in proportion and is widely sep- 

 arated from the large ventral limb of the clavicle, except at the 

 dorsal edge, where they are in contact. 



The hypercoracoid is a miniature replica of the correspond- 

 ing bone in Xiphactinus. The facets for the articulation of the 



