ON THE CCUM COLI OF THE CAPYBARA. 313 
50. ON THE C4#CUM COLI OF THE CAPYBARA 
(HYDROCHGRUS CAPYBARA).* 
Ix no work on anatomy with which I am acquainted can I find any Page 19. 
reference to the peculiarities of the cecum coli of the Capybara, which 
are but an extreme exaggeration of those observed in many of the 
allied forms. | 
In most of those mammals in which a cecum is present, that 
organ is simply a direct continuation backwards of the colon beyond 
the place of junction of the small and large intestines. In some 
Rodents, however, this is not the case, the sacculated cecum in them 
not being a direct continuation of the larger gut, but a lateral diverti- 
culum from a true but simple cecum. 
Tn his account of the anatomy of Capromys fournieri,t Prof. Owen 
remarks that the arrangement at the ileo-colic junction is such that 
“the two orifices of the blind intestine [that into the ileum and that 
into the colon] are analogous to the cardia and pylorus of the stomach;” 
and in his “ Anatomy of Vertebrates,”’{ the same illustrious author 
tells us, with reference to the same animal, that “the cecum is marked Page 20. 
off from the colon by a valvular structure, similar to that at the end 
of the ileum.” This is an approximation to the condition which 
obtains in the animal under consideration. 
In the Capybara the small intestine enters the enormous sacculated 
cecum at about an inch from its open extremity, and its relations to it 
are not in any way peculiar. The sacculated cecum is nearly two feet 
long, and is traversed by four longitudinal bands. At its open end, 
which is an inch beyond (that is, further from the cecal extremity 
than) the ileo-cecal valve, it is constricted by a circular sphincter 
muscle, which forms the orifice of communication with the rest of the 
cylindrical large intestine. The colic surface of this sphincter is 
situated in the side of the colon, three inches from the blind extremity 
of a true, simple, thick-walled, slightly pyriform cecum, which is 
directly continuous with the colon, and is indistinguishable from it in 
structure. This second cecum is, as indicated above, three inches 
from the extreme end to the centre of the orifice by which it com- 
municates with the sacculated one. Superficially its longitudinal 
muscular coat is strongly marked, covering it perfectly uniformly. 
* “Proceedings of the Zoological Society,’ 1876, pp. 19-22. Read, Jan. 4, 
1876. 
t+ “Proceedings of the Zoological Society,” 1832, p. 70. 
I Vol. iii. p. 425. 
