| OCR Text |
Show 1895.] TEETH OF CERTAIN POISONOUS SNAKES. 823 viewed from the side, the lower half of the tooth is seen to be very narrow and much attenuated. The apical portion of the tooth is thus compressed antero-posteriorly. The groove is relatively much larger than in the other geuera (vide PL X L V I . fig. 21), and reaches to within a short distance of the apex, opening by a small (anterior) aperture on the flattened surface of the tooth; the opening at the base of the tooth is large. Besides the two grooved teeth there is also a small and much bent tooth, with a very obtuse apex, situated on the outer edge of the maxilla slightly nearer to the posterior end. Genus DISTIRA. Species examined:-D. cyanocincta. The glands are very similar to those of Enhydris (PL X L V I. fig. 1). The superior labial gland is greatly developed anteriorly, and the poison-gland is much rounded posteriorly and slightly constricted in the middle. The inferior labial gland is long and narrow, and the Harderian gland (PL X L V I . fig. 17) possesses a larger posterior lobe than either Enhydris or Platurus. The maxilla (PL X L V I . fig. 8) has two anterior grooved fangs, the outer one a little posterior to the inner, which are proportionately smaller than those in the two previous genera. There is a considerable interspace, and then 8 smaller teeth forming a somewhat irregular series. The first two or three only of these teeth showed any indications of a groove \ This was so in the maxillae of two specimens. In transverse section the grooved fangs are almost circular. Genus HYDRUS. Species examined :-H. platurus and H. platurus var. alternans. The superior labial gland is not so large as in the three previous genera. The poison-gland is partially under cover of a mass of muscular tissue; it is long and narrow, is partially constricted in the middle, and extends inwardly a considerable distance (PL X L V I . figs. 3, 6, and 7). The Harderian gland is not differentiated into two lobes, and is comparatively smaller than in the other genera examined (PL X L V I . fig. 16). The maxilla (PL X L V I . tig. 10) possesses two anterior grooved fangs, the inner one being slightly anterior in position to the outer one. After a short interspace there is a series of 7 or 8 smaller teeth of equal size; these latter are more crowded posteriorly. The grooved fangs are slightly compressed laterally, and the groove extends very far down the tooth and is tightly closed even when quite close to the apex (PL X L V I . fig 20). 1 Boulenger (' The Fauna of British India: Beptilia and Batrachia,' London, 1890) describes these posterior maxillary teeth as being grooved. Also in P.Z.S. 1890, p. 618 (" Remarks on a Skull of Distira cyanocincta horn Ceylon"), he mentions a large skull which possessed grooves on the mandibular teeth. There were no grooves on any of the mandibular teeth in the specimens I examined. |
