OCR Text |
Show 820 MR. G. S. WEST ON THE BUCCAL GLANDS AND [Nov. 19, (PL XLV. fig. 11) possesses 14 teeth. The 3 anterior ones are of small size and separated by moderately large diastemata, then follow 8 closely-set teeth of slightly larger size, and after a small interspace the 3 posterior teeth. These latter do not form a continuous series with the others, but are set along the edge of the posterior expanded end of the maxilla. The first two are large and grooved, but the third is very small and solid. This is the only case I have yet met with in Opisthoglyphous Snakes where a solid tooth follows the grooved ones. The poison-gland of L. annulata is clearly defined from the superior labial gland, and is of the more usual form. The Harderian gland is not externally visible on removal of the skin as in L. rufescens (PL X L V . fig. 13). The maxilla (PL X L V . fig. 14) has 9 small, rather stout teeth of uniform size, followed by 2 posterior large and rather straight grooved fangs. There are 9 mandibular teeth. Genus HOMALOPSIS. Species examined :-H. buccata. The poison-gland in this Snake is very clearly defined and somewhat sigmoid in form. The superior labial gland does not extend so far back as usual, but is otherwise rather extensive. The inferior labial gland is also of considerable bulk, and all three glands exhibit a marked lobulation (PL X L V . fig. 20). The Harderian gland is of a most unusual form, only a small anterior lobe being within the orbit, whilst a large irregularly lobulated posterior portion lies under cover of the poison-gland (PL X L V . fig. 24). The maxilla has altogether 12 teeth (PL X L V . fig. 21). The first 11 are solid and of equal size, set very close together, and possess a character which is quite unique amongst the Snakes that I have examined. In transverse section, the anterior face of the tooth is seen to be quite plane, and there are two lateral cutting-edges ; the posterior surface (which is in section about two-thirds of the arc of a circle) is longitudinally ridged (PL X L V . fig. 22). There are eight or nine of these ridges near the base of the tooth, but tbey run out towards the apex, near to which the tooth becomes almost triangular. The posterior tooth is much larger than the rest and is grooved; it is somewhat irregular in transverse section and the groove is widely open (PL X L V . fig. 23). Genus CERBERUS. Species examined :-C. rhynchops. The only specimen of this Snake examined had the head considerably damaged, and one maxilla was all that could be isolated in an uninjured condition (PL X L V . fig. 25). It possessed 17 teeth, which were in one continuous series, the posterior one being a little larger than the rest and grooved. This and the preceding genus belong to the Homalopsince or Freshwater Snakes. |