Apr. 1903. North American Plesiosaurs — Williston. 43 



membrane bone to attain on the visceral side of all three cartilage 

 hones. The anterior border is gently thickened, somewhat sinuous 

 in outline, and is free for a part of its extent. The other borders are 



Fig. 8. 



Diagram <>( pectoral girdle of Dolichorkynchops osborni^ from above; the outlines of con- 

 cealed parts are indicated by dotted lines. lc, episternum (interclavicle); cl., clavicle; sc. % scap' 



ula; <().. coracoid. 



thin, for the most part squamous, and nowhere free, save for a short 

 distance at the anterior end of the coraco-scapular foramen, and the 

 posterior part of the interclavicular foramen. The two bones meet 



