| OCR Text |
Show 1870.] DR. J. E. GRAY ON THE DERMATEMYD.E. 715 small, separate or united together into one plate. Intramarginal plates three on each side ; the hinder in contact with the abdominal and femoral plates. Abdominal plate long. Axillary plate distinct. Tail conical, with a central ridge of spines on its upper surface, and some scattered tubercles on the sides converging towards the point. 1. DERMATEMYS MAWII. Gular plates very small, separate, Dermatemys mawii, Gray, P. Z. S. 1847, p. 56 ; Cat. Shield Rept. p. 49, t. xxi. Dermatemys mavei, Cope, Proc. Acad. Nat. Sc. Phil. 1868, p. 120. Hab. South America (Mawe). B.M. 2. DERMATEMYS SALVINII. The gular plates united into a single narrow triangular plate ; sides of the head and neck and upper surface of the feet olive, darker-spotted. In spirits. Dermatemys salvinii, Gray, P. Z. S. 1864, p. 126 (animal). Hab. Guatemala (Salvin). B.M. I cannot see any other difference between these two species except the form and union of the gular plates. I believe this is permanent ; but we require more specimens to establish the fact. The head and sides of the neck of Mr. Salvin's specimen, in spirit, are pale olive with numerous darker spots ; and the feet have some similar spots. There is a little difference in the size of the intermarginal plates of the two specimens, but not more than shown on the two sides of Mawe's original specimen. Mr. Cope describes his T. berardii thus : - " One gular, and an in-tergular behind it; four or five inner marginals, the posterior in contact with femoral and abdominal; when only four, the median elongate ; vertebral scuta much longer than broad ; no dorsal keel; abdominal scuta equal or broader than those adjoining." I suppose that this character is from a Mexican specimen. M. A. Dumerii's plate does not show any of them. The existence of any gular plate would indicate an irregularity in the specimen, or a structure which has not hitherto occurred to me, and, if normal, would remove the species to Hydraspidae. 2. CHLOREMYS. Head rather convex above. Thorax rather depressed, broad. Nuchal shield distinct and short. Vertebral plates keeled ; the first as broad as long; the second, third, and fourth broader than long; the fifth rather narrowed in front. The gular plates small, united into one narrow triangular shield. The intramarginal plates three on each side ; the hinder largest and not, or only slightly, in contact with the femoral plate. Axillary plate triangular. Inguinal bandlike, transverse. Tail conical, very short, granular. |
