as 
102 THSTUDO. 
shaped; and the last of the series is rhomboidal, and is included in the notch of the 
latter and one similar of the pygal plate. 
The costal plates are alternately broader and narrower. 
In the recent condition, the carapace is invested by corneous scutes, which impress 
it with their form. 
There are five vertebral scutes, four pairs of costal scutes, and eleven marginal 
scutes upon each side of a narrow symmetrical nuchal scute and a broad undivided 
pygal scute. 
The plastron or sternum of Zestudo is composed of a single, more or less pyri- 
form, entosternal plate, inclosed by a pair of episternal and hyosternal plates, and 
posterior to the latter of a pair of hyposternal and xiphisternal plates. 
ims ns 
Fig. 2. Ideal view of the structure of 
the sternum of Testudo. en, entosternal 
plate; ep, episternal plate; hyo, hyosternal 
plate; hyp, hyposternal plate; xi, xiphi- 
sternal plate; gu, gular scute; pe, pectoral 
scute; hu, humeral scute; ab, abdominal 
scute ; fe, femoral scute; ca, caudal scute ; 
Imp—l11mp (right), marginal plates of the 
carapace; 1ms—11ms (/e/#), marginal scutes 
of the carapace; ns, nuchal scute; ps, py- 
gal scute; 9, 10vp, vertebral plates; pp, 
pygal plate. 
The corneous scutes of the sternum, which impress their osseous basis, consist of 
eight pairs, as follows: the gular, pectoral, humeral, axillary, abdominal, femoral, 
inguinal, and caudal scutes. 
Dr. Evans, in the Geological Report of Dr. Owen, before quoted, states that fossil 
turtles were found in a portion of the Bad Lands, some five or six miles in extent, 
having much the appearance of an ancient lake, where it is entered from Bear 
Creek, a tributary of the Cheyenne. At one of these lake-like expansions hundreds 
of fossil turtles were discovered. They do not rest immediately on the grassy plain 
that forms the present floor or bottom, but on the talus and debris, collected into 
