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Show 1904.] OX THE CIRCULATORY SYSTEM IX THE OPHIDIA. 331 5. Contributions to our Knowledge of the Circulatory System in flic Ophidia. By F R A X K E. B E D D A R D, M.A., F.R.S., Prosector to the Society. [Received February 4,1904. J (Text-figures 67-78.) So far as I am aware, the detailed accounts of the arteries and veins in Snakes, which have been published by previous observers, are comparatively few in number, though of course a great deal has been ascertained about the more important arteries and veins in a considerable number of types. I have therefore attempted in the following remarks to embody, as briefly as possible, the facts which I have verified in a number of different snakes which. have been specially injected with a coloured substance for my purpose. M y observations have chiefly been made upon the arterial system, though I am able to add something to our knowledge of the details in the venous system here and there. For the most part the species of snakes which I have examined differ from those studied by previous observers. I have, however, come to the conclusion that a vast amount of work in this branch remains to be accomplished before the knowledge of the circulatory system is at all adequately known in detail. For I find that in the summary given in Bronn's ' Thier-Reich ' * the details are not always fully stated, not indeed through omissions to report upon existing literature, but through the absence of great detail in that literature. Many of the older writers, for instance, have only dealt with certain regions of the arterial system. Thus Rathke t, writing upon the single or double condition of the carotid, gives also much information upon the arteries of the head and neck in general; and his account is the completest original account known to me of these arteries, though in Bronn's ' Thier- Reich' it is made still more complete by the incorporation of other work. Brandt J again has concerned himself with the persistence of a ductus botalli joining the carotid and the left arterial aortic arch ; while Hochstetter § has figured and described portal veins. The latter authority has compiled an excellent list of previous memoirs dealing with the venous system. The list-given in Bronn is also most useful. In the present paper I attempt to do for a number of different * ' Klassen und Ordnungen des Thier-Reichs,' Bd. vi. Reptilien, Abth. iii. Schlangen. Leipzig, 1890. The older and well-known works of Meckel, Cuvier, and Milne- Edwards contain a good many facts. f " Bemerkungen fiber die Carotiden der Schlangen," Denkschr. k. Akad. Wien, \i. Abth. 2, p. 1 (1856). This memoir has no plates or figures. X " Leber einen eigenthumlichen spater meist obliterirenden Ductus Carotis der gemeinen Kreusotter Pelias bents," Bull. Ac. Imp. Sci. St. Petersbourg, ix. 1866 p. 274. g Morph. Jahrb. six. (1893). |
