292 MEMOIRS OF THE CARNEGIE MUSEUM 
fibulare represented in the drawing, it being difficult to determine what may have 
been its outline. 
The first toe is short, the second, third, and fourth of nearly similar moderate 
elongation, and the fifth somewhat elongate, as set on the strongly bowed and en- 
larged metatarsal V., which is similar to that common to all sea turtles. 
The first toe bore a heavy and free claw, and I believe the claws of toes II.-IV. 
were also free and clawed, as indicated by their form and the curvature of the an- 
tero-lateral or ungual ridges. Reference may be made to Fig. 6, showing the 
lateral view of all the ungual phalanges which were all dissociated. 
Allusion has been made to Professor Williston’s restoration of the hind limb of 
Protostega," and, before pass- 
ing on to a general comparison 
with other forms, it is neces- 
sary to deal with this restora- 
tion more specifically. Willis- 
ton’s figure is that of a form 
so different from Protostega and 
all other turtles, that, if cor- 
rect, it would indicate the ex- 
istence of a new and hitherto 
unknown genus, or even fami- 
ly, of marine turtles. But this 
cannot be; for the form and 
proportions of the individual 
elements is throughout essen- 
Fic. 6. Protostega gigas. Ungual phalanges. f, fingers; h, toes. 
Lateral view. 4%. (Trial series not found to necessarily be the exact tially thesame as in Protostega. 
pugerand tpeiseries:) The fact is that the arrange- 
ment of elements given by Professor Williston affords no approximation, and no 
direct hint as to the tarsal organization in Protostega. Metatarsal V. is placed in the 
position of metatarsal I., and the bone supposed to be metatarsal V. is probably from 
another animal, or else, the metatarsal of the other flipper is much altered by the 
compression to which nearly all the turtles from the Kansas chalk have been sub- 
jected. The other tarsals are difficult to adjust, although it is in particular likely 
that the element placed in the fibular position is a pisiform; for in both form and 
proportions it agrees with the pisiform of both of the present specimens, and differs 
very markedly in these respects from the true tarsal elements. The phalangeal 
16 See foot-note 7. 
