84 
October 26, 1841. 
William Yarrell, Esq., Vice-President, in the Chair. 
The following communication, entitled, ‘‘ Description of the Sto- 
mach of the Colobus Ursinus, Ogilby,”’ by R. Owen, Esq., was read. 
«The body of the Ursine Colobus, which there can be little doubt 
is the Full-bottom Monkey of Pennant (Colobus polycomos, Illig.), 
lately exhibited in the Society’s menagerie, having been transmitted 
to me for examination by Mr. Waterhouse, with a view more par- 
ticularly to the determination of the form of the stomach, I have 
much pleasure in communicating to the Society the result of this 
examination. 
“Tt may render the interest in the dissection of this Monkey more 
intelligible to some, if I premise, that the genus to which it belongs 
is one of recent discovery or establishment, the affinities of which to 
the Doucs (Semnopithecus), though strongly illustrated by the general 
form of the Colobi, and more especially by their skull and dental 
organs, required a knowledge of the anatomy of their digestive sy- 
stem for its full appreciation. 
“The Colobi, peculiar among all known old world Simiade by the 
rudimental development of the thumbs of the fore-hands, were gene- 
rically separated on that account by Illiger. Cuvier, at the period of 
publishing the last edition of the ‘ Régne Animal,’ had not enjoyed 
the opportunity of determining how far the distinctive character, seized 
. upon by the Berlin naturalist, was real and constant. Temminck, 
however, had assured Cuvier that the Colobus of Illiger possessed the 
skull and dentition of the Semnopithect. Mr. Ogilby has mainly 
contributed to establish the Illigerian genus and illustrate its extent 
by the description of several species founded upon skins transmitted 
to the Zoological Society ; and our excellent establishment has now 
fulfilled another of its functions, by affording to the anatomist the 
means of establishing the natural affinities and position of the genus 
Colobus, as it has heretofore done in regard to the Semnopithecus. 
“The stomach of the Colobus Ursinus presents the same compli- 
cated saccular structure as in the Semnopitheci : if it was somewhat 
smaller in the present instance, in proportion to the body, this might 
arise from the immaturity of the individual examined. The saccula- 
tion is produced by the same modification of the muscular fibres of 
the stomach, combined with a great extent of the digestive tunics. 
A narrow band of longitudinal fibres traverses the lesser curvature 
of the stomach, and a second band, commencing at the left or blind 
extremity of the cavity, puckers it up ina succession of sub-globular 
sacs along the greater end. I deem it unnecessary to pursue the 
description more minutely in this case, as it would be merely the 
