| OCR Text |
Show 1869.] DR. J. E. GRAY ON THE TORTOISES. 217 3. TRIONYX. The odd bone of the dorsal disk covered with a pitted coat in the young animals. The genus may be divided into sections thus : - * Head short, broad (about as long as broad at the ear-bone), rounded in front. The alveolar surface of the lower jaw concave, with sharp raised inner and outer margins, and an indistinct short central ridge on the inner side of the front. The central palatine groove in front of the internal nostrils very wide, as wide in front as behind. 1. TRIONYX GANGETICUS. * * The head rather elongate (rather longer than the breadth at the ears), rather tapering in front. The alveolar surface of the lower jaw as wide in front as on the sides, slightly concave, with a central longitudinal ridge across the front, and with a slight concavity on each side. The central anterior palatine groove shallow, narrow in front and wide behind. 2. TRIONYX JEUDI. (Fig. 19, p. 218.) Hab. Java ? From the Museum of Prof. Lidth de Jeude. This species is described from a fine adult skull received from the Utrecht Museum, which, no doubt, was obtained from some of the Dutch colonies. It is most distinct from the Indian species. I have named it after the Professor who formed the Museum. The front longitudinal ridge is very distinct in the jawbone, almost more so than in the horny beak of the jaw. The front of the jaw of the T. gangeticus is simply concave, without any indication of a ridge, but only a slight prominence on the inner part of the inner edge; and the alveolar surface on the sides of the iower jaw is flat and with a deep oblong concavity on each side. In the British Museum there is the head of an adult animal in spirit that was purchased of Mr. Theobald, who obtained it in Pegu. It has the narrow central anterior palatine groove, and the cylindrical ridge across the front of the lower beak, of this section of the genus ; but the ridge is only slightly raised and very different from that in the skull from Utrecht. 3. TRIONYX FORMOSUS. (Plate XV. fig. I.) This species is described from a young specimen in spirit, procured by Mr. Theobald from Pegu. The back shield olive, with four very large black-eyed spots, the central spot circular, black, with a narrow white margin, and a dark brown ring close to it, which is surrounded by a larger pale brown ring, separated from the inner one by a broad olive space. The outer ring forms part of a regular series of netted dark lines, which are symmetrical on the two sides of the keel, forming a large open space in the middle of the back, and a smaller one near the margin and on the hinder part of the disk. The underside of the margin of the disk sooty grey, paler in part, with a white edge on the margin |
