42 



HAY. 



[Vol. II. 



If I have correctly determined the bone figured here (Fig. 8), 

 the supraclavicular, by its great length, compensated for the 

 shortness of the post-temporal. Its length is about equal to 

 that of the parasphenoid. 



The shoulder girdle has received very unfortunate treatment. 

 It appears to have been misunderstood by both Professor Cope 

 and Dr. Crook, being by both writers described 

 in an inverted position. Cope gives figures in 

 his Cretaceous Vej'tebratcs as follows: PI. XL, 

 Fig. 9 (cleithrum .?) ; PI. XLII, Figs. 2-5; PI. 

 XLIV, Figs. 10, II. Most of these depict 

 the scapula and the parts immediately adjacent. 

 Cope describes the " coracoid " as a stout flat 

 rod, narrower than the cleithrum (clavicle), 

 and appressed to the inner face of the latter 

 nearly to its distal end {Cret. Vert., p. 186). 

 He was unable to state whether or not there 

 was present a precoracoid, but said that the 

 " coracoid " occupied the position of the pre- 

 coracoid in some fishes. According to his 

 conception, the scapula was placed high up on 

 the body, although his restoration of the fish 

 on PI. LV does not so indicate. Dr. Crook 

 has presented figures of the girdle of Xiphac- 

 Pl. XVII), of his IcJitJiyodectes polymicrodtis 

 (PI. XVI) and of /. anaides (PI. XV). There can be no doubt 

 that all these figures represent bones which belong to the side 

 of the body opposite to that to which they are assigned, and 

 that what is regarded as the ventral end is the dorsal. To 

 demonstrate this it is only necessary to compare the figures 

 with the prepared shoulder girdle of a shad. Dr. Crook 

 recognized that Professor Cope's coracoid was really the pre- 

 coracoid; nevertheless, he has represented it as running ventrally 

 from the coracoid, instead of toward the dorsal end of the 

 cleithrum. 



One result of Crook's error is that the coracoid is brought 

 into a position dorsad of the scapula. The materials employed 

 by both Cope and Crook were defective, that portion of the 



Fig. 8. — A", tiiolossits 

 Suprascapula ? x 3. 



tinus {op. cit., 



