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VII. On the sacculated Form of Stomach as it exists in the Genus Semnopithecus, F. Cuv. 
By Ricuarp Owen, Esq., F.Z.8., Assistant Conservator of the Museum of the Royal 
College of Surgeons in London. 
Communicated June 11, 1833. 
IN the dissections of the animals of the class Mammalia which take place at the Mu- 
seum of the Society, it rarely happens that the more important organs are found to 
present any remarkable deviations from the structures already known and described as 
characterizing the genus or group to which the species under examination may belong. 
Nor is it to be expected that novelties of much importance can often be detected in a 
class which has been so extensively investigated. Nevertheless, the necessity of con- 
tinuing these examinations at every opportunity that occurs, must be admitted by every 
one : anatomical facts become more valuable to the physiologist as their authenticity is 
confirmed by repeated examination ;—the means of forming conclusions as to the reci- 
procity of function, and the relative value of different organs, from their varying pre- 
ponderance in different animals whose habits as burrowers, swimmers, climbers, &c., 
may affect the different functions ;—these interesting and important deductions can 
only be founded on extensive tabular arrangements of the weights and admeasurements 
of the different organs. But whilst the anatomist is silently accumulating these data, 
it does happen every now and then that unexpected modifications of important organs 
present themselves, the discovery of which, while it serves as a healthy stimulus to his 
exertions, at the same time teaches him how dangerous it is to draw hasty conclusions 
as to analogy of internal structure from similarity of external form. 
The singularly shaped stomachs which are now before the Society were taken from 
two species of a genus of Monkey, the Semnopithecus, F. Cuv., which in the system of 
Cuvier ranks only fifth in the descensive gradation from Man. This genus is of late 
formation, and not entirely the result of newly discovered materials : several species, on 
the contrary, were for a long time ranked with the Guenons, Cercopithecus, in which 
the stomach is of the usual simple construction: and it is almost superfluous to remark 
in this place, how slight is the essential zoological character, viz. an additional tubercle 
on the last molar of the lower jaw, which distinguishes genera presenting such wide 
discrepancies in the most important of their vital organs. 
The larger of the two stomachs was taken from a full-grown female Entellus Monkey, 
Semnopithecus Entellus, F. Cuv., which measured, from the end of the nose to the root 
of the tail, 1 foot 8 inches. The admeasurements of the stomach, distended and dried, 
are as follows :— 
VOL. I. K 
