TESTUDO NEBRASCENSIS 567 
TESTUDO NEBRASCENSIS.  Leidy. 
(Tab. xii. a, figs. 1, 2.) 
Stylemys Nebrascensis: Pr. Ac. Nat. Sci., vol. v. 172. 
Testudo Nebrascensis: ib., vol. vi., 59. 
This species was first characterized as belonging to a new genus, under the suppo- 
sition that the processes which rise upwards from the sternum to aid in the support 
of the carapace were distinct bones, a mistake which arose from their unusual size 
and prominence, and their being detached by fracture from the sternum. 
In Dr. Owen’s collection, there are two specimens of this species, varying in size, 
and in some degree in minute anatomical detail. Both have the marginal plates 
broken away in front and behind, and the larger has lost nearly all its carapace, 
and the smaller the anterior portion of the sternum. The carapace of the smaller 
specimen has a vertebral plate in excess introduced between the eighth and the V- 
shaped plate. 
The species is more depressed than the Gophir, and has more the form of the 
Kmydes than the Testudines. The sternum is flat, and the axillary and inguinal 
notches are directed downwards. 
The marginal plates are quite oblique above, and turn abruptly under at their 
lower third. The bones are relatively thick and strong. 
In the smaller specimen the first vertebral plate is ten lines long and six broad. 
Those from the second to the eighth inclusive are hexahedral; the anterior four 
being the larger and nearly equal in size. The ninth or accessory plate is trans- 
versely oblong, quadrilateral. 
Each vertebral plate after the first to the eighth inclusive, articulates with two 
pairs of costal plates. 
The first costal plate externally articulates with the first to the third marginal 
plates, but does not quite reach the fourth. The vertebral scutes from the second 
to the fourth inclusive, are hexahedral, and broader than long. 
The sternum agrees in its characters in both specimens, except in the smaller, the 
anterior border of the humeral scute courses along the posterior edge of the axilla, 
whereas, in the larger, at its external part, it turns forwards and outwards to the 
axilla. 
The entosternal plate is pyriform, and is longer than it is broad, and encroaches 
upon the position of the gular scutes. 
In the larger specimen the episternals are one and a half inches long. The 
hyosternals are two and a quarter inches long, and articulate with the third to the 
fifth marginal plate inclusive. 
The hyposternals articulate with the fifth to the seventh marginal plates. 
The gular scutes are angular posteriorly. The humeral scutes internally are six 
lines long, and externally expand before and behind, and join the axillary and the 
fourth and fifth marginal scutes. 
