| OCR Text |
Show 1895.] TEETH OP CERTAIN POISONOUS SNAKES. 819 There were two posterior, almost straight, grooved teeth (PL I. fig. 25), preceded by a few small teeth which were larger anteriorly. The mandibular teeth were 10 in number, the 3 anterior ones large and followed by 7 smaller teeth. Genus PSAMMOPHIS. Species examined :-P. sebelans. The only available specimen of this Snake had been at some period dried, and consequently the teeth only could be examined. The maxilla (PL X L V . fig. 19) possessed 10 teeth-three anterior small ones followed by a diastema, then two large teeth and three more small ones ; the two posterior teeth were large grooved ones. There were 13 mandibular teeth, 2 anterior large ones and 11 very small ones; the first 3 small ones were separated by wide diastemata, and the 8 posterior ones grouped together. Genus TRIMERORHINUS. Species examined :-T. rhombeatus. The poison-gland is here superficially indistinguishable from the superior labial gland, and extends a comparatively long distance posterior to the eye (PL X L V . fig. 17). The maxilla possesses 10 teeth; the 2 posterior ones are very large and grooved, and the 8 anterior ones are much smaller and of uniform size. Genus THAMNODYNASTES. Species examined :-T. nattereri. The poison-gland is very clearly differentiated from the superior labial gland and exhibits a marked lobulation. The maxilla is somewhat slender and possesses altogether 16 teeth ; the 2 posterior ones are large, grooved teeth, and the other 14 are smaller, much attenuated teeth (PL X L V . fig. 15). The grooved teeth possess a small, though marked, posterior cutting-edge (PL X L V . fig. 16). The mandibular teeth are also 16 in number, but are not so crowded as the maxillary ones and are more upright. Genus LEPTODIRA. Species examined: -L. rufescens and L. annulata. The poison-gland of Leptodira rufescens is superficially indistinguishable from the superior labial gland, and is of a most extraordinary form. Just posterior to the eye it has a sudden upward flexure, and is then continued backwards for a much greater distance than that observed in the gland of any other Opisthoglyphous Snake (PL X L V . fig. 10). Looking at the head from the side, the gland is seen to partially cover the lower portion of the eye; but, to compensate for this, the head is very broad and the eyes' directed obliquely upwards and forwards. The maxilla |
