CE'CIIM (Lat. crocus, blind), a blind sac; that is, a sac or bag having only one open. ing, connected with the intestine of an animal. In man there is only one C., very small, and apparently not performing any important function, situated at the extremity of the small intestine, where it terminates in the large intestine or colon. In many of the mammalia, however, and particularly in most of those which are herbivorous, it is com paratively large, and is found to secrete an acid fluid resembling the gastric juice. It therefore appears that, where the nature of the assimilatory process is such as to require the detention of the food for a considerable time, this provision is made for it, in order that digestion may be more completely accomplished. The C. is entirely wanting in some quadrupeds, as in bats, and the bear and weasel families. Birds have two men., which are generally long and capacious in those that are omnivorous or granivorous, and the position of which is the only circumstance that marks the division of the intes tine into two parts, the small and the large intestine, or the ileum and the colon. In
reptiles, a C. is of very rare occurrence. Fishes have none in the position occupied by those of quadrupeds and birds, but many of them have caeca attached to the intestine at its uppermost part, and very generally regarded as appendages of the stomach. The number of these coca is, however, extremely various; sometimes there are only 2, and sometimes more than 100. The number is different even in very nearly allied species of the same family; thus, there are only 6 in the smelt, but 70 in the salmon; 24 in the herring, and 80 in the shad. In some fishes, as the cod, the caeca consists of large trunks ramified into smaller ones.—The intestinal canal of some of the infusoria is furnished throughout its whole length with numerous ctcca, no other organ corresponding to a stomach appearing to exist.