420 FOSSIL TURTLES OF NORTH AMERICA. 
All the tarsalia of fig. 559 (2, 3, 4, 5, of the second row) are present in the right foot 
except the first; but this is present in the left foot. The first and the fifth are largest. By its 
inner border the fifth articulates with the fifth tarsal; and by a part of the lower border, with 
the fourth metatarsal. The metatarsals of the first and second digits and the first phalangeal 
of the second digit are missing; but these are present in the left foc The distal, claw-bearing 
phalanges are relatively long, that of the first digit being 27 mm. long; that of the second, 35 
mm.; that of the third, 40 mm.; and that of the our, 37 mm. Back claw phalange is there- 
fore as long as, or longer than, ‘the remaining phalanges, together with the metatarsal of the 
same digit. In size acd form the distal phalanges reeomible those of Gopherus polyphemus. 
The terminal portion of the tail is greatly expanded. This portion is 75 mm. long and 
appears to consist of 5 vertebra. The leteral processes of these vertebra are lengthened, so 
557: 
Fics. §57 AND 558.—Testudo oshorniana. Shell and femur of type. 
557. Carapace, side view. X¢#. 558. Left femur, ventral surface. 4. 
that a broad Hat beaver-like paddle is produced. Its greatest breadth is 85 mm. The terminal 
vertebra, 10 in number, of G. polyphemus have their lateral processes similarly lengthened, 
but in this case the processes are distinct, true caudal ribs, 
This tortoise possest the same kind of supplementary armor that we have found in 7. 
orthopygia. ‘The skin of the bottoms of the feet, of the lower leg, of the hinder part of the 
thigh, the tail, both on the upper and the lower sides, and probably also of the anterior limbs 
supported an armor composed of bones of various sizes. These bones doubtless lay each 
beneath a horny scale such as we see protecting the limbs of many of the living species of 
Testudo and of other genera of turtles. Fig. 559 represents the dermal bones, as well as the 
foot bones of the right hind foot. The dermal bones evidently belonged to the bottom of the 
foot and the hinder portion of the lower leg. The deeper surface of these bones is seen, as is 
indicated by the pitting. The external surfaces, where seen, are smooth. In the figure the 
tarsal bones and the phalanges are lettered. It will be observed that the dermal bones of the 
foot and the heel are larger than those further up on the leg. How far up on the leg they 
extended is uncertain. 
Fig. 560 shows the dermal bones which protected the upper surface of the tail and of the 
hinder portions of the thigh. In the center of the mass is seen a considerable area consisting 
of about a dozen bones closely articulated suturally. These overlie the expanded extremity 
of the tail, of which the last centrum and its processes (fig. 560, 4, 4) are seen resting on the 
hinder border of the carapace. On the left side of the fgure the dermal bones adjoining the 
