WIELAND : THE OSTEOLOGY OF PROTOSTEGA 293 
formula of 3, 3, 3, 3, 0, as proposed by Williston, is not that of Protostega, in which 
the true formula is 2, 3, 3, 3, 3. 
The strongly marked angular tubercle of the proximal end of the fibula, as 
figured by Williston, reminds one of the similar and similarly situated process on the 
femur of the Dinosaur, Camptosaurus. It is not present in any of the specimens of 
Protostega known to me, and must at least indicate a new specific form. Should 
further examination confirm the presence of this feature, the specimen in the collec- 
tion of the University of Kansas, which shows it, should be known as the type of a 
new species. And surely its most appropriate name would be one honoring the dis- 
tinguished paleontologist who first studied it, and who rendered a very distinct ser- 
Fic. 7. Toxochelys latiremis. Left front flipper. Dorsal view. a, head; 6, radial condyle ; c. ulnar condyle; e, 
ectepicondylar groove; g, entocondyle; R, radius; U, ulna; Jn, intermedium; Ul, ulnare; C, centrale; 1-5, first 
to fifth carpalia ; P, pisiform ; I.—V., first to fifth metacarpals and fingers. 
vice by figuring it as best he could in the absence of further material or means of 
checking results. 
Structurally, aside from the more primitive clawed condition, there is no hiatus 
between the tarsal and other features of the hind flipper of Protostega and the exist- 
ing sea-turtles, the comparison with Dermochelys being quite as close as any other, in 
some respects closer in fact than with a somewhat aberrant although primitive form 
like that of Colpochelys (Fig. 8). In Dermochelys and Protostega the relative size and 
development of all the tarsal elements is suggestively alike. It is indeed increasingly 
difficult to believe that the former genus belongs to an utterly remote and primi- 
tively separated line. But unfortunately there is not yet known amongst the fossil 
marine turtles a single hind flipper which is sufficiently well preserved to afford 
