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Show 1 9 0 4 .] ON THE VISCERAL ANATOMY OF PELAGIC SERPENTS. 147 head of the brephos lying apparently within the gullet, and at any rate anteriorly in the body, might arrive at a conclusion opposed to the real facts which more accurate observation reveals. One rather important piece of evidence is commonly omitted in those cases of alleged swallowing of the young, which I refer to here for other reasons, and only incidentally as concerned with popular beliefs. Each brephos has not only the small white vesicle adherent to the body already referred to, but considerable vestiges of the other embryonic sacs invest and are attached to it. These are distinguishable by their grey colour, and are comparatively bulky. In the case of one brephos, they are attached to it ; in the case of the other, the young one came away from the membranes, which were found to be attached to the mesenteries, and possibly in process of being absorbed. Any suggestion of protection by the mother within her body of actually born young would of course lie negatived by these facts. 5. Contributions to the Knowledge of the Visceral Anatomy of the Pelagic Serpents Hydrus platyurus and Platyurus colubrinus. By F r a n k E. B e d d a r d , M.A., F.R.S., Prosector to the Society. ^Received May 20, 1904.] (Text-figures 26-28.) In the comprehensive works of Milne-Edwards * and Meckel t and others, there are numerous references to various points in the anatomy of the pelagic Ophidia, while a more particular account of the viscera of one species has been given by Cantor +. The lungs have been particularly dealt with, though very briefly, by Oope§; while Mr. G. W. Butler || has incorporated remarks upon some of these snakes into his general papers upon the asymmetry of the Ophidian lung. Both the last-mentioned papers contain references to previous literature. I have had the opportunity of dissecting one example each of the marine snakes Hydrus platyurus and Platyurus colubrinus which have been in my possession for some time, the latter specimen belonging to me, the former to the Prosector's Stores. This dissection enables me to add something to our knowledge of the anatomy of the Hydrophiinse, and to compare two quite distinct generic types. I had not expected to find them so different as dissection showed them to be. (1) Platyurus colubrinus. The specimen of this snake which I dissected measured in all nearly 17 inches, of which a little over two belong to the tail. * ‘ Lecons sur la Physiologie et l'Anatomie comparee.' f * Anatomie compare.' French Transl. x " Observations upon Pelagic Serpents," Trans. Zool. Soc. ii. p. 303. <5 " On the Lungs of the Ophidia," Proc. Am. Phil. Soc. xxxiii. 1894, p. 217. || In P. Z. S. 1892, p. 477, and P. Z. S. 1896, p. 691. |