TOXOCHELYID. 167 
/ 
nearer their respective borders of the humerus. ‘To the present writer the principal changes 
which have affected the thalassic and parathalassic humeri, as represented by Caretta ane 
Dermochelys, are to be found in the straighte ning of the shaft; the change of the head from a 
position looking upward, in the natural position of the bone, to one iGokine toward the median 
plane of the animals the descent of the radial process, on the shaft; the transference of this 
process, or of a component of it, toward the radial border; and the removal of the condyles 
for the radius and ulna and of the ectepicondylar foramen or groove toward the ulnar border of 
the bone. Of all these changes none seems to have taken place in Toxochelys, except a slight 
descent of the radial process. In every other respect the bone retains the characteristics of 
Chelydr a. 
In many other features the fore limb of Toxochelys has made approaches to the flipper of 
the marine turtles, as Dr. Wieland has shown. The ulna, as compared with that of Chelydra, 
has become shorter relatively to the humerus while the radius has 
become longer, as it has also to a greater degree in Caretta. The ulna 
has become shorter than the radius, and the third and fourth fingers 
have become greatly elongated; but in these respects it is far behind 
Caretta. The first and second fingers retain about the same ratio to 
the humerus that they have in Chalyara: Taken altogether, the limb 
may be regarded as standing between that of Chelydr a and the sea- 
turtles but nearer to that of C helydra. From the fact that the head of 
the humerus had the position that it has in the freshwater turtles and 
that the phalanges possest well-developt condyles we may be quite cer- 
tain that the species of Toxochelys had no difficulty in getting about 
on the land. 
The first and second fingers of Toxochelys were composed of 
phalanges which were much stouter than those of the other fingers. 
The terminal phalanges were encased in horn and formed strong 
curved claws. The other fingers did not probably extend beyond the 
border of the skin. Dr. Case (op. cit., plate Ixxxii, figs. 1, 2) repre- 
sents the first finger as having 3 phalanges. This figure is evidently 
that of the second finger. 
Fic. 201.—Toxochelys The following measurements are taken from Dr. Wieland’s des- 
sp. indet. “Vibia, fb- cription of the fore limb in Yale University Museum (fig. 200): Length 
ula, and some foot ¢ : és ee ere S : u 
aes of humerus, 135 mm.; radius, 75 mm.; ulna, 66 mm. 3 total length 
4 of the first fnger, 65 mm.; of second finger, 95 mm.; of third finger, 
estimated, 130 mm.; of fourth finger, estimated, 135 mm.; of fifth finger, estimated, go mm. 
The pelvis is somewhat more like that of Caretta than like that oe Chelydra. Dr. Case 
has given figures of the ilium (op. cit., plate Ixxxi., fig. 8) and of the ischium (op. cit., pl. Ixxxi, 
fig. 6). The antero-lateral processes of the pubis are broader than they are in Chelydra. 
The femur is not an uncommon bone in collections of Toxochel ys materials. Figures of 
the bone are presented by Case (op. cit., plate Ixxxi) and Leidy (op. cit., plate xxvi, fg. 18). 
Unfortunately the bone is usually crusht, so that its exact form is questionable. It is certain, 
however, that the greater and the lesser trochanters were separated by a deep fossa, as Case 
has dascrived the bone. This fossa was probably like that found in Chelydra. In Caretta 
and again in Testudo this fossa 1s nearly obsolete. Case believed that the femur was a weaker 
bone than the humerus. This view is probably correct, and is corroborated by the relative 
izes of the humerus and femur figured by Leidy. It is not certain, however, that these bones 
belonged to the same individual. ite G helydr athe femur is the longer bone. 
Whe tibia and fibula are not well known. There is presented i in fig. 201 a portion of the 
hinder limb in the possession of the author and believed to belong to T oxoc helys. The tibia 
and fibula are elongated and slender, more like those of Chelydra than like those of Caretta. 
Four tarsals are present. The metatarsal is probably that of the first toe. Case (op. cit., p. 378 
describes the hind foot of an incomplete specimen, but the error 1s made of assigning pik 
phalanges to the first digit. The digit may have been the second, including the metatarsal. 
The terminal claw was strong and eiuck curved. The phalanges of the remaining digits were 
longer and slenderer, and the terminal one did not support a claw. 
