OCR Text |
Show 18/9.] ANATOMY OF HY.ENA CROCUTA. 89 the same number of lobes as in H. striata ; but this was not the in our specimen. In Proteles the subdivision of the lungs resembles that in H. striata, but differs in the presence of two notches in the anterior border of the middle lobe on the left side. In respect, therefore, of the form of the lungs, H. crocuta differs more from either of the other species than they do from each other. Vascular System. Heart.-Is short and broad, as in the other species of Hycena. Its cavities present the usual characteristics of the carnivorous heart. The fossa ovalis is clearly defined. There is no trace of a Eustachian valve. The aortic arch gives off two large trunks, of which that to the right is the innominate, which, as in the majority of Car-nivora, divides into the right subclavian and right and left carotids. The second branch is the left subclavian. The trunk of the abdominal aorta gives off close to its termination the two external iliac arteries, and after a further course of 1 inch divides into the two internal iliac and caudal arteries. The origin of the external and internal iliac arteries as distinct branches of the abdominal aorta appears to be a somewhat unusual occurrence, so much so that it is mentioned by Prof. Huxley2 as one of the characteristics of the Didelphia. Whether this arrangement occurs in other species of Hycena is not mentioned by those authors who have examined them. Urinary and Generative Organs. Kidneys.-Are situated very far back, the posterior extremity of each lying in the iliac fossa. The surface is smooth, and presents no trace of lobulation. They are globular in form, and much resemble the renal organ in the true Felidae. As in them, a number of arborescent veins ramify upon the surface of the organ. On section, the kidney is seen to be composed of a single large pyramid, provided with a single papilla, and consequently differs in this respect from that of H. brunnea, in which, according to Dr. Murie2, the cones are eight in number, at least in the cortical portion. In II. striata, Hunter3 found a similar arrangement to that described in II. crocuta. The remaining portions of the urinary and sexual organs have been described before4. BRAIN. The brain of H. crocuta so closely resembles in all respects that of Proteles, of which an excellent description has been given by Prof. Flower5, that we have thought it unnecessary to enter into any lengthened description of this organ. At the same time, having regard to his observation that the brain of the Hyaena has not hitherto 1 ' Manual of Anatomy of Vertebrated Animals,' p. 327. 2 Trans. Zool. Soc. vol. vii. p. 507. 3 ' Essays and Observations,' by Owen, vol. ii. * Proc. Zool. Soc. 1877, p. 369. and 1878, p. 417. 5 Pror. Zool. Soc. 1869, p. 478. |