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Show 1880.] MR. Wr. A. FORBES ON THE UAKARI MONKEYS. 635 As far as can be judged from the few examples given in this table, Brachyurus rubicundus apparently has a greater absolute, and even greater relative, length of intestines and caecum than any other New-world Monkey, including even the considerably larger Lagothrix. This would seem to indicate that in its native forests Brachyurus is more of a vegetarian than its allies. There are no valvulae conniventes. Peyer's patches are almost confined to the last yard of the ileum, there being 14 large and well defined ones in that space, the largest § inch long. There is a large one close to the ileo-caecal aperture. Higher up only a few can be found ; and they disappear in the jejunum. The caecum is in no degree sacculated, neither is the colon. The former, which is of considerably larger calibre, is cylindrical, blunt, and curved on itself when distended into more than a circle, with a well-developed median peritoneal frsenum. The general form and proportions of the liver may be seen in figs. 3 & 4 (pp. 636, 637), representing respectively the diaphragmatic and visceral (superior and inferior) aspects of that organ. Regarding its form in the Cebidae we are told by Prof. Flower, in his lectures on the digestive system of the Mammalia (Med. Times and Gaz., M ay 4, 1872, p. 509), that "all the members of this group in which he has been able to describe the liver, agree in the depth to which the lateral fissures cut up the organ into its four principal lobes, and also in the great development of the caudate lobe, which is the principal character by which they can at once be distinguished from the Old-world families." In both these respects, as will be seen by an inspection of the figures, the liver of Brachyurus is perfectly Cebine. The two lateral fissures extend very nearly, at least on the superior surface, back to the posterior (attached) margin of the liver. The four principal lobes are very distinct; the left central is markedly smaller, as is often the case in the Cebidae, than the three others, which are here all very nearly equal. The left lateral lobe is decidedly thin along its outer margin; the other lobes are thick, and of simple form ; the right lateral is much longer antero-posteriorly than transversely. The caudate is large and square ; on its visceral surface it is marked by a conspicuous diagonal ridge running from the entrance of the vena cava towards its postero-external angle. It develops two well-marked though small fissures, but is otherwise simple. The right lateral lobe appears internally to it, when viewed from below. The Spigelian is an elongated, somewhat clavate thickening, which is not free, but is most developed on the left side. The umbilical fissure is well-marked, extending for about one third of the total median depth of the liver. There is no trace of a cystic notch; and the gall-bladder, which is large, does not reach by some little distance the anterior (free) margin of the liver. It lies very superficially, and, as in most of the Cebidae (though not in Cebus itself or in Atcles), lies very close to, and almost in, the umbilical fissure. An accessory lobule, developed at the internal angle of the left central lobe, helps in large part, on this side, to form a shallow cystic fossa. A second similar, but smaller, partly free lobule is also developed |