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Show 1889.] FAT-BODIES OF T H E SAUROPSIDA. 603 Page V. On certain Subcutaneous Fat-deposits 609 VI. On the fatty "Spleen "of the Crocodiles 610 VII. Conclusions 611 VIII. Explanation of the Plates 612 I. INTRODUCTORY. _ The conditions under which the investigations of which this paper gives the results were commenced and carried on were stated in the introduction to m y paper upon the Subdivision of the Body-cavity, read at the last meeting (see above, p. 452). II. ON THE RELATIONS OF THE FAT-BODIES OF THE SAUROPSIDA, AND ON CERTAIN POINTS IN THE ANATOMY OF MONITORS. The fat-bodies referred to are those which, as is well known, occur in Lizards on the course of the "pelvic" veins, and of more or less of the anterior-abdominal vein. The vessels named, with their tributaries, take away the blood, which is brought to the fat-bodies by large branches from the anterior of the two pairs of arteries that supply the hind limbs, and which I take to be homologous with the femoral arteries of birds. Corresponding fat-bodies are very conspicuous in the Snakes (cf. figs. 8, 9, & 10 ca), where, as in the Snake-like Amphisbsenidse, they extend from the cloaca to the hinder margin of the liver (cf. figs. 4, 5, 6, 7). The figures of sections of Adder and embryo Grass- Snake show that, when the fat is well developed, the peritoneal cavity of Snakes may be much restricted by reason of the fact that the kidneys and fat-bodies lie outside it. The latter occur in the Crocodiles, but, as described below, the fat-bodies here referred to are in these animals more lateral in position than in Lizards ; and in the case of the birds, the fat-laden " omentum," or transversely expanded ventral ligament of the stomach, is, I think, obviously comparable, so far as its fat is concerned, to the similar fat-laden ventral ligament in such forms as the Amphisbsenidae and Snakes, where the fat extends forwards as far as the liver. The Chelonia are the only order of the Sauropsida in which I have not observed these structures well developed, but there appear to be traces of them in Emys europcea \ In many Lizards (cf. fig. 11) these fat-bodies, pushing the peritoneum before them, bulge into the body-cavity ; and, lying on the course of the large vessels ventral to the (once respiratory allantoic) bladder (cf. figs. 7 & 12) and the alimentary canal, into the ventral ligament of which they in some forms (Amphisbsenidse, fig. 4) obviously extend, they may form paired masses quite as conspicuous in the posterior part of the abdominal cavity as are the liver-lobes in the anterior half2. 1 I have only examined in this connection some half-dozen specimens of Emys and Testudo, and those not large ones. 2 These lie of course, ventral to the alimentary canal and lungs. Passing over the important difference that no branching system of tubules extends from 4 0* |
