160 



THE EXTINCT BATRACHIA, REPTILIA 



probaWy in contact with marginal bone till maturity. These ooetal bones are gently curved, and with longitudinal 

 shallow grooves of sculpture. 



Fisr. 4:i. 



The, individual of which the greatest num- 

 ber of fragments is preserved, is from near 

 Barnesboro, shows that the retiaulate sculp- 

 ture of the marginal bones at the bridge is 

 distinct above, obsolete below. There are 

 three and parts of two others in the bridge 

 in Platemys and Emydoids; three of those 



of P. sulcatus Leidy are known; two of 



those of the present species are preserved. 

 Both have been wholly attached to the plas- 

 tron ; one has an acute, but not thin or 

 recurved outer margin; the other is strongly 

 obtuse. All three of those of T. sulcatus 

 are, according-to Leidy, thin and recurved. 



Length of obtuse marginal, 

 Width of inferior face 



///,. Lin. 

 ,2 (i 

 I 9 



The edges of the anterior marginals are 



thin and acute, not revolute nor notched. 



In. Lin. 

 Width margin of median vertebro- 



marginal bone, 1 8 - 



Width marginal scutum, next it, 2 6. 



Length " " 2 4.5 



The free lateral margin of the hyposter- 

 nal is obtuse, not thickened or grooved, 

 thinning a, little near the suture with the 

 xiphisternal. 



The sternum in general is not thick hi 

 this specimen; in flic thickest portion of the 

 bypo-hyosternal suture 5 lines; in a, frag- 

 ment of another no doubt larger specimen, 7.5 lines. The mesosternum, with the derma] sutures is fortunately lire- 

 served; the former is transverse diamond shape. The oharacter of the plastron, except the hyosterhal region, may 



be learned from the accompanying cuts of restorations. A cut of the axillary pit and its position is also given. 



In a, line specimen from I lornerstow n, for which I am indebted to Jno. (J. Meirs, the lateral InterstemaJ hones are 

 easily seen. They present a, rounded interior outline, and apply to an equal extent of the hyo- and hypostcrual hones. 

 They extend but one third the distance to the median longitudinal suture, and are much as in the Podocnemis of the 

 Amazon. Posterior lobe of plastron 10.5 in. wide, between inguinal notches. 



One of the costal hones from Tinton falls exhibits the pit for the inguinal buttress. It differs from that of the 

 pubis of the other specimens, and of P. prinoeps and P. enodis in not being situated on an elevated ridge or pedestal, 



-<CJ 



