608 ON ARCTOCEBUS CALABARENSIS 
The spleen (fig. 8) is 1°5 inch long and o%3 inch wide in the middle ; 
it is very flat, and tapers to each end. It is attached by the lesser 
omentum to the cardiac end of the stomach, and does not extend along 
its great curvature. The alimentary canal thus much resembles that 
of the Potto (Van der Hoeven, 2 ¢& pp. 50,51). In the latter, however, 
the stomach forms a small czcal dilatation beside the pylorus, and the 
colon is sacculated, though the cecum is devoid of sacculations. 
Neither in the Potto, nor in Ofolicnus pelt, nor in Tarszus, is there any 
appendix vermiformis, though Schroeder van der Kolk, and Vrolilk 
find it to be represented in Nyetzeebus (Recherches d’Anat. Comp. sur 
le genre Stenops). 
The liver appears to be somewhat more subdivided than in the 
Potto, but not more than in Svtexops (Sch. K. & V.). The ductus 
choledochus opens much nearer the pylorus than in either Zarszvs or 
the Potto, in which it ends in the descending part of the duodenum. 
The pancreas is divided into lobes in 7arszus, Otolicnus, and Stenops 
(Schroeder van der Kolk and Vrolik). The spleen is confined to the 
cardiac end of the stomach, not attached along its greater curvature 
as in Zarszus, the Potto, Wycticebus, and Loris. 
The arterial part of the vascular system of the Angwantibo had 
been partially injected by Mr. Murray, with the view of determining 
the existence and the nature of any retia mirabilia which might exist. 
Mr. Murray was unfortunately prevented, however, from carrying his 
examination of the specimen, while freshly injected, further than the 
brachial artery, which, he writes, exhibited “a longitudinally striated 
appearance. JI meant to have dissected these striations fully and 
delicately out, and expected to find that they were composed of a 
series of vessels. .. 1 reasoned that it would answer the same 
purpose, whether the artery was broken up into many branches spread 
all about the arm, or packed in one tube...... When I last 
looked at it the striations were much less visible than at first. At 
first they were wondrous distinct.” 
Unacquainted with these observations, I, at first, nearly failed to 
make out the existence of any rete mirabile in either the upper or 
the lower extremities. Occupying the place of the brachial and 
femoral vessels, I found what had all the appearance of simple 
trunks, filled evenly, though imperfectly, with the red injection-mass ; 
and it was only on finding myself unable to pass a fine style into the 
supposed arteries, that I was led to examine their structure more 
minutely by the help of transverse sections and the microscope, 
Each trunk now turned out to be a dense and firm cord of connective 
tissuc, traversed longitudinally by multitudinous trunks, some of 
