k 



ACTINEMYS MARMORATA. 465 



the adult; groins scaleless also; rest of the limbs scaly; five fingers 

 and four toes, clawed, palmated to the base of the nails. Tail 

 slender and tapering, protected by large quadrangular plates. Out- 

 line of carapax subelliptical, anteriorly subconcave, posteriorly 

 notched, with a vertebral bony ridge. Surface of the bones rugose, 

 granular or striated ; epidermis smooth in the adult. Anterior 

 edge of the plastron rectilinear ; posterior edge broadly angular. 



Syn. — Actinemys, Agass. Contr. Nat. Hist. U. S. Amer. I, 1857, 444. 



Observ. — For the above generical diagnosis, w^e alone must be held 

 responsible, since the genus is anything but characterized by its author, 

 in the work we have just quoted. The margin of the upper jaw, gene- 

 rally straight in the young, is rather convexly curved in the adult, 

 and the notch at its anterior extremity may be observed in other 

 genera. The radiating and granular striae, which are observed upon 

 the scales in the young, are not altogether peculiar to it, for they may 

 be found to a greater or less degree not only in Testiido tahidaia, but 

 in several of the genera occurring within the limits of North America. 

 Moreover, these striae not only affect the scales, but may be observed 

 upon the bony plates, constituting the carapax itself, the scales merely 

 reflecting a structure which primarily belongs to the plates alluded 

 to. By removing the scales, the surface of these bones will exhibit 

 traces of that structure, even in the adult, although the scales may 

 assume a perfectly smooth appearance. 



ACTINEMYS MARMORATA (Ag.), Grd. 



(Plate XXXII.) 



Char. spec. — Carapace eUiptico vel suhelUptico plus minusve convexo, 

 carina vertebrali ossea obtusa. Sterno suhenipsoideo, antrorsum quam 

 retrorswn latiori. Memhrls squamosis ; squamis in facie anteriori 

 magnis, non imbricatis, in facie posteriori modicis, subiuberculosis. 

 Unguibus robustioribus. Cauda supra carinata, subconica et miniL- 

 ente. Supra plerumque fusca-olivacea, nigro marmorata ; infra 

 flavescente, in aduUo unicolori, in jmiiore vero per abdominis re- 



gionem nigra. 



117 



