OCR Text |
Show 816 MR. G. S. WEST ON THE BUCCAL GLANDS AND [Nov. 19, The arteries supplying the Harderian and poison-glands arise from the ophthalmic artery which crosses the lower half of the orbit. The branch to the Harderian gland arises from one side, and that to the poison-gland on the other, just before this artery enters the orbit. The branch to the poison-gland enters that about the middle and then bifurcates, one branchlet running anteriorly and one posteriorly. Side by side with these arteries there run corresponding veins. The labial glands are supplied by branches of the maxillary and mandibular arteries. These statements are based upon observations made upon the undermentioned genera, each of which may now be dealt with in greater detail. Genus DIPSAS. Species examined:-D. irregularis, D. ceylonensis, D. fusca, and D. dendrophila. The poison-gland in all the species is clearly definable from the superior labial gland; the latter extends anteriorly but a short distance in D. fusca (PL XLIV. fig. 1) and D. ceylonensis, whereas in D. dendrophila and more especially in D. irregularis it extends to the anterior extremity of the jaw. The inferior labial gland is also more extensive in the latter species. The lobules are much smaller in D. fusca and D. irregularis than in D. ceylonensis and D. dendrophila. The Harderian gland is two-lobed in D. fusca and D. ceylonensis (PL XLIV. figs. 6 and 7), but three-lobed in the other two species, two of the lobes being within the orbit (PL XLIV. fig. 5). The maxilla of D. fusca (PL XLIV. fig. 2) possesses much fewer teeth than those of the other three species. There are 7 solid teeth and 3 posterior grooved teeth; of the latter, two are large ones and the third is much smaller and more curved. D. dendrophila and D. irregularis each possess 3 posterior grooved maxillary teeth, the terminal one in each case being the smallest (PL XLIV. fig. 4). The maxilla of the former has 12 solid teeth and that of the latter 14. The maxilla of D. ceylonensis (PL XLIV. fig. 3) possesses 2 large grooved teeth of equal size and 12 solid ones. Genus DRYOPHIS. Species examined :-D. prasinus and D. mycterizans. The poison-gland in this genus is proportionately smaller than in any other genus examined, and superficially is not readily distinguished from the superior labial gland (vide PL XLIV. fig. 11). The Harderian gland is of very small bulk and consists of a mere strip of glandular tissue under and posterior to the eye (PL XLIV. fig. 14). The maxilla of D. mycterizans (PI. XLIV. fig. 13) possesses 4 anterior small teeth, three median large ones, then 5 more small ones, and finally two large grooved teeth. That of D. prasinus (PL X L I V . fig. 12) possesses 5 anterior small teeth, a median very large and stout tooth, then 4 more small ones, and finally one large grooved tooth. The grooves of the posterior maxillary |