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Show 1 9 0 5 . ] ANATOMY OF THE LEATHERY TURTLE, 319 In the specimen examined by Vaillant there Avere in the stomach remains of Hyperia galba, fragments of Medusa?, as well as 20 grms. of plant-debris. I have also come across a statement in Tickell's ‘ Kept ilia ' that, according to Audubon, the food of this Turtle consists of Mollusks, Fishes, Crustaceans, Sea-urchins, and various marine plants. Its diet appears, then, to be chiefly animal. O rgans of C ir c u l a t io n . The Heart. The heart agrees with that of other Chelonia in all essential characters. It differs, however, from the normal condition in shape, being somewhat long and narrow instead of peculiarly broad. The length is chiefly due to the narrowness and elongation of the ventricle, the apex of which tapers to form a very long and stout gubernaculum cordis attached distally to the pericardium. In connection with the question of shape, it is interesting to note that Rathke* mentions that in embryos of Chelone the heart is relatively longer and narrower than in the adult. The great trunk-veins open into a sinus venosus of moderate size, which in turn opens into the right auricle by a long slit-like orifice the axis of which slopes from below upwards and to the right, and which is guarded laterally by a pair of simple valves. The posterior wall of the sinus venosus is attached by a stout band of splanchnic pericardium containing the coronary vein to the right upper part of the ventricle. A similar band is figured by Fritsch t in the hearts of Chelhyclra serpentina and Crocodilus ; and I have seen one in Testudo indica, but it is apparently absent in Chelone. The left auricle, as usual, is relatively very small, being not more than a quarter the size of the right. The pulmonary veins unite as they enter it, and their common opening is protected to some extent by a valvular flap, formed by a prolongation of its upper and outer lip into the auricular cavity. As a rule, in the Chelonia the opening of the pulmonary veins into the auricle is not valved in any way. The interauricular septum is convex towards the left auricle. Its lower edge is thickened and longitudinally split to form a valve for each aui'iculo-ventricular opening. The walls of the auricles are very thin in comparison with those of Chelone my das and show little trabecular structure. The cavity of the ventricle is peculiarly small and scarcely extends half way to the apex. The lower half of the ventricle, * Rathke : Entwickl. p. 210. f Fritsch : " Zur vergl. Anat. der Amphibienherzen," Arch. f. Anat. 1869, p 737, pi. 17. fig. 2, and pi. 18. fig. 2. P r o c . Z o o l , S o c .-1905, V o l . I . No. XXI. 21 |
