1880.] MR. W. A. FORBES ON THK UAKARI MONKEYS. G35 



As far as can be judged from the few examples given in this table, 

 BracJujurus rubkundus apparently has a greater absolute, and even 

 greater relative, length of intestines and csecum than any other New- 

 world Monkey, including even the considerably larger Layothrix. 

 This would seem to indicate that in its native forests Brachyurus 

 is more of a vegetarian than its allies. 



There are no valvulpe 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-csecal aperture. Higher up only a few 

 can be found ; and they disappear in the jejunum. The csecum 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 mav be seen in figs. 

 3 & 4 (pp. 636, 637), representing respectively the diaphragmatic and 

 visceral (superior and inferior) aspects of that organ. R,egarding its 

 form in the Cebidse we are told by Prof. Flower, in his lectures on the 

 digestive system of the Mammalia (Med. Times and Gaz., May 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 prin- 

 cipal 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 tlie 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 Cebidse, than the three others, 

 which are here all very nearly equal. The left lateral lobe is de- 

 cidedly 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 super- 

 ficially, and, as in most of the Cebidse (though not in Cebiis itself 

 or in Aides), lies very close to, and almost in, the umbihcal fissure. 

 An accessory lobule, developed at the internal angle of the lei\ cen- 

 tral lobe, helps in large part, on this side, to form a shallow cystic fossa . 

 A second similar, but smaller, partly free lobule is also develo[)ed 



4 '2* 



