WIELAND: THE OSTEOLOGY OF PROTOSTEGA 287 
features of the humerus are, however, highly characteristic, as is shown more 
particularly in Figs. 3 and 4, which disclose certain approximations to the 
humerus of Dermochelys not so readily discernible in the figures hitherto pub- 
Lgl, 
‘i ay i he Gi 
j Wi ay yy 
i } i I) y i if 
Fia.3. Protostega gigas. Ental view of alargehumerus. Actual length, 34cm. «, head ; b, radial crest ; c, ulnar 
condyle; d, ectepicondyle ; ¢, ectepicondylar foramen ; f, ectocondyle ; g, entocondyle, 
lished. It must be noted, however, that crushing has been such as to greatly dimin- 
ish the distal breadth and render it uncertain as to whether there is an ectepicon- 
dylar groove. Case speaks of a foramen in describing his specimen," though his 
figure suggests a groove. I suspect that there may be present a true enclosed fora- 
men rather than a deep groove as in Archelon. In the latter the groove is much 
further back from the anterior border and the ectepicondylar process correspond- 
ingly larger, while the radial crest is not nearly so prominent as in Protostega. (See 
Fig. 3.) 
1! See foot-note 5. 
