CHELONIA. 73 



The entosternal plate (6-) forms an almost regular rhomb ; the episternals (es) are 

 much broken, and offer no peculiarity in the parts which remain ; nor is there, in the 

 general form of the hyosternals (h) or hyposternals (ps), or the xiphisternals (xs), 

 anything which calls for particular notice. 



The contour of the bony case, viewed as a whole, bears out the close relation to 

 the terrestrial form which I have assigned to this species. The slightly curved costal 

 regions of the carapace, and the even flatness of the vertebral portion, as well as the 

 outline of the dorsum, when view^ed laterally, show a very striking approximation to 

 the small African species of true Testudo, T. areolata, and still more to T. si(jnala. But 

 if its geological position did not of itself preclude our considering it as belonging to a 

 terrestrial group, the structure of many parts of its osteology would be sufficient to 

 justify our considering it as a true Emydian. 



Inches. 

 Length of the carapace . . . . . . . . . 3*2 



Breadth of ditto 2-9 



Height of the bony case . I'S 



T. B. 

 Emys bicarinata. Bell. Tab. XXV and XXVI. 



The specimen before me, the only one which I have yet met with of this species, 

 is very large, and, from the close union of the bones, and the nearly obliterated 

 condition of the sutures, is evidently of considerable age ; a fact also attested by the 

 forms of the vertebral scutes {v2, vz, v4, T. XXV), which have become greatly narrowed 

 in proportion to their length. 



The general outline of the carapace must have been nearly orbicular. The 

 elevation moderate ; the part occupied by the vertebral scutes, and about half an inch 

 on each side of them, flattened ; and this plain portion bounded on each side by a low 

 obtuse carina, which is itself obscurely and irregularly grooved longitudinally. The 

 sides are considerably sloping, with but a slight curvature. 



The carapace is wanting anteriorly in nearly the whole of the nuchal plate, and 

 posteriorly from the tenth neural inclusive. At the sides a few fragments only of the 

 marginal plates exist. 



The first neural plate (^i) is nearly oval, and, as usual in this family, is wholly 

 included wuthin the first pair of costal plates ; it is considerably longer than any 

 of the succeeding ones. The second neural (.s'2) is nearly as broad as it is long, the 

 anterior angles truncated as usual, posteriorly somewhat narrowed ; the third neural (ss) 

 has the peculiarity of being longer than even the second, and is less narrowed behind ; 

 the fovirth to the seventh inclusive («4-7) are gradually shorter, the seventh forming a 

 broad hexagon, with the lateral angles (meeting the costal suture) nearly midway 

 between the anterior and posterior margins. The eighth {ss) is also broader than it is 



10 



