1904.] ON THE A^ISCERAL ANATOMY OF PELAC4IC .SERPENTS. 147 



head of the brephos lying appai-ently within the gullet, and at 

 a.ny rate anteriorly in the body, might ari-ive at a conclusion 

 opposed to the real facts which more accurate obsei'vation 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 Avhite 

 vesicle adherent to the body already referred to, but considerable 

 vestiges of the other embiyonic sacs invest and are attached to it. 

 These are distinguishable by theii- grey colour, and are com- 

 paratively 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 

 membi'anes, 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 coui'se be negatived by these facts. 



5, Contributions to the Knowledge o£ the Visceral Anatomy 

 of the Pelagic Serpents llydrus platyurus and Platyurus 

 coluhrimu. By Frank E. Beddard, 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 i-ef erences 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 t. The 

 lungs have been particularly dealt with, though very briefly, by 

 Cope§ ; while Mr. G. W. Butler i| 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 

 i-eferences to previous literature. 



I have had the opportunity of dissecting one example each of 

 the marine snakes Hydrus platyurus and Platyurus coluhrimis 

 wliieh 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 Hydi-ophiinse, and to compare two quite dis- 

 tinct generic types. I had not expected to find them so different 

 as dissection showed them to be. 



(1) Platyurus coluljrmus. 



The specimen of this snake which I dissected measui-ed in all 

 nearly 17 inches, of which a little over two belong to the tail. 



* ' Lemons sur la Physiologic et I'Anatomie comparee.' 



t ' Aiiatoraie comparee.' French Transl. 



X " Observations upon Pelagic Serpents," Trans. Zool. Soc. ii. p. 303. 



§ " On the Lungs of the Ophidia," Proc. Am. Phil. Soc. xxxiii. 1894, p. 217. 



II In P. Z. 8. 1892, p. 477, and P. Z. S. 1896, p. 691. 



