1909.] OF MONKEYS OF THE GENUS PITUECIA. 937 



The first two inches of the colon are sacculated, and the 

 very deep sacculations are sliown from the inside in the illus- 

 tration (text-fig. 291, p. 935). There were three of these, the first 

 being larger than the two following. Along one side of this 

 sacculated region of the colon was a distinct taenia, but not on 

 the other. 



The liver is represented in text-fig. 292 from the abdominal aspect. 

 It will be seen to present no very I'emarkable features, and is 

 very like those of other Platyrrhine Monkeys, e.g. Callithrix 

 (see Beddard, 1, pi. xi. figs. 1, 2). The left lateral lobe gives ofi' 

 to the I'ight two sid:)sidiary outgrowtlis, of which one covers over 

 the cystic duct and nearly touches the i-ight lateral lobe *. 

 The well marked Spigelian lobe is divided into three lobules. 

 The bile-duct joins the cystic duct about half aia inch from their 

 common orifice into the duodenum. There is practically no 

 lie'pato-renal ligament, and the Jiepato-caval ligament is very short, 

 lying just above the right kidney and not extending as far down 

 as it. These ligaments agree according to my experience with 

 the corre.sponding ligaments of Cebus flavescens. 



§ Heart and. Blood-vessels. 



The accompanying illustration (text-fig. 293, p. 938) exhibits 

 the intei-ior of the right ventricle with the auriculo-ventricular 

 valve and the papillary muscles attached thereto. The free wall 

 of this ventricle is beavitifully sculptured, the sculpturing being 

 in excess of that which is sometimes met with in the same wall of 

 the light ventricle of other mammals. I do not, however, wish to 

 be understood as suggesting that this very marked sculpturing of 

 the free ventricular wall is a character of the species or of the 

 genus. The sculpturing forms a basketwork towards the middle 

 of the wall of this ventricle ; superiorly, near to where the 

 auriculo-ventricular valve takes its origin, five or six strap-like 

 bands free themselves altogether from the meshwork ancl run 

 approximately parallel to each other to end upon the attached 

 margin of the valve. The three cusps of the ti-icuspid valve 

 itself are each provided with a papillary miiscle, all of which are 

 shown in the figui'e referred to. The middle papillary muscle 

 arises, as is sometimes the case in other mainnuds, from the fi'ee 

 wall of the ventricle. In common with the moderator band 

 arises a slender papillaiy muscle which ends in chordse tendinese 

 attached to the septal half of the valve collax ; and another 

 papillary muscle, also ending in connection with the septal half 

 of the valve collar, lies close by and is also indicated in the 

 accompanying text-figure. 



The precise ari'angement of the intei'costal arteries varies so 

 much among mammals that it is always worth while to describe 



* This almost free flap of hepatic tissue occurs in several monkeys. I have 

 myself recorded it in Callithrix (as has Weldon) and in the ally of the present 

 species, Pithecia alhinasa (3, p. 364). 



