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Show 824 MR. G. S. WEST ON THE BUCCAL GLANDS AND [Nov. 19, There is a mass of much-convoluted blood-sinuses all round both tbe mandibular and maxillary teeth. These attain a most astounding development in this animal, and are the most conspicuous objects present in any section (whether longitudinal or transverse) containing the teeth. They were present in the other genera examined but to a smaller degree, whereas in the four specimens of this Snake examined they were enormously developed and to the same extent on both sides of the head. These sinuses fill up the interstices between the teeth and also extend a considerable distance on both sides of the jaw; they completely surround the whole of the reserve teeth. It is impossible to consider that all this blood is required by the teeth, as many other Snakes have comparatively much larger teeth than this, yet do not possess any marked development of these sinuses. They are supplied by very large blood-vessels, and their function appears to be that of aquatic respiration: if so, w e have to deal with accessory organs of respiration, analogous to the villous processes present in the mouths of soft-shelled Turtles (Amydet mutica and Aspidonectes spirifer1), and it is worthy of remark that spongy outgrowths of the mucous membrane serving a somewhat similar function occur in the Electric Eel (Gymnotus), but that here they may be utilized for aerial respiration by an animal whose respiration is normally aquatic2. EXPLANATION OF THE PLATES. PLATE XLIV. Fig. 1. Dipsas fusca: head from left side. Note.-In all tbe figures of the heads the skin has been removed, the connective tissue, &c, cleared away to show the glands, and the folds of the mucous membrane of the mouth about tbe maxilla and mandible removed to expose the teeth ; the glands, however, often lie externally to the teeth in such a manner as to hide them. Fig. 2. Dipsas fusca: left maxilla from below. 3. Dipsas ceylonensis : left maxilla from below. 4. Dipsas dendrophila: „ „ „ 5. Dipsas irregularis: Harderian gland (eye removed). 6. Dipsas fusca: eye removed, to show Harderian gland. 7. Dipsas ceylonensis: eye removed, to show Harderian gland. 8 ,, „ : transverse section of grooved tooth. 9. Dipsas fusca: „ „ „ „ 10. Dipsas dendrophila: „ „ „ „ 11. Dryophis prasinus: head from left side. 12. „ „ : left maxilla from below. 1 Simon H . Gage, " Pharyngeal Eespiration in the Soft-shelled Turtle," Proc. Amer. Assoc. Adv. Sci. 1884, pp. 316-318. Simon H . & Susanna Phelps Gage, " Aquatic Eespiration in Soft-shelled Turtles," Amer. Nat. vol. xx., 1886, pp. 233-236. This accessory respiration also takes place in Trionyx: vide Louis Agassiz, Contrib. Nat. Hist, of the U.S.A. vol. i. (Boston, 1857), pp. 283, 284. 2 Cf. Oleland, Notes on the Viscera of Gymnotus electricus," Memoirs and Memoranda in Anatomy, vol. i. art. ix. pp. 90, 91, pi. x. figs. 2, 3. |