COPE.] PALEONTOLOGY MIOCEXE PERIOD. 511 



TESTUDINATA. 



TESTUDO, Linn. 



Eemains of species of this genus are very abundant in the Miocene of 

 Colorado, and present much greater variety of structure than do the tor- 

 toises of the White Eiver beds of Dakota. This is most strikingly seen 

 in the forms of the lobes of the plastron, which may be flat and trun- 

 cate, deeply bifurcate or produced into a wedge-shaped process. I have 

 distinguished four species, as follows : 



Testudo CULTRA.TTJS, Cope, Pal. Bull., No. 15, p. C. 



This species introduces several from the same formation as the Pelto- 

 saunis, which agree with the existing genus Testudo in their short, stout 

 metapodial and phalangeal bones, and single anal scutum of the cara- 

 pace. 



In the present species, the prominent peculiarity is seen in the form of 

 the lip of the anterior lobe of the plastron, each half of which is an 

 elongate pyramid, its depth and width being equal. The marginal bones 

 were short, stout, and recurved. Length of carapace nearly 18 inches. 



Testudo laticuneus. Cope, Pal. Bull., ISTo. 15, p. 6. 



In this species, the anterior lip of the lobe of the plastron is very 

 prominent and wedge-shaped, and with dentate margin, and is flat and 

 thin. The posterior lobe is sub truncate. The mesosternal bone is hex- 

 agonal and broader than long, and is pointed behind. The pygal bone 

 is triangular, and the anal marginal is convex in both sections and 

 abbreviated below. Each marginal bone behind the bridge presents a 

 mucro, where a dermal suture reaches the margin. Anal scutum very 

 wide. All the sutures double lines. Length from 18 inches to 2 feet j 

 width two-thirds the length. Carapace rather flattened. 



This is the most abundant species of the formations ; several good 

 specimens obtained. 



Testudo asiphithoetax. Cope, Pal. Bull., No. 15, p. 6. 



Anterior lobe of plastron broadly truncate, scarcely lipped; j)os- 

 terior lobe openly emarginate. Mesosternum longer than broad, acute 

 in front, very obtuse behind. All the sutures simple. Anal marginal 

 shortened but convex. Form depressed. Length and width as in the 

 last. 



Testudo ligonius, Cope, Pal. Bull., No. 15, p. 6. 



Posterior lobe of plastron produced into two flattened, sharp-edged, 

 wedge-shaped processes, separated by a deep notch, as in Sadrianus 

 corsonii. Marginal bones behind very wide, or, considered separately, 

 long and narrow, with a step-like angle and notch where the scutal 

 suture reaches the margin. 



The form of the anterior lobe of the plastron is yet uncertain, though 

 fragments found with the type resemble that of T. laticuneus. At least 

 three incomplete specimens obtained. 



STYLEMYS, Leidy. 



Stylemys nebrascensis, Leidy; Testudo nchrascensis, Leidy, Report 

 Geol. Surv. Terrs., (4to,) vol. i, p. 339. 



