ANAL GLANDS. Under this name may be described a large and diversified group of glands, found in many animals, and generally characterized by the disagreeable odor of their secretion. Those to which the name most strictly belongs are of frequent occur rence among carnivora and rodents; they consist of follicles which pour their secretion into sacs with muscular walls and narrow orifices, placed one on each side of the anus. According to the most recent investigations, it appears that these sacs are to be consid ered as prolongations inwards of the common integument, and that two sorts of glands open into them; one of a lobulated•structure, having a fatty secretion, and representing U. K. I.-27 the sebaceous glands of the skin greatly hypertrophied; the other crowded more at the bottom of the sac, tubular, and elaborating the specific secretion. In the hyena, there is a single sac, which opens by a transverse fissure above the vent. There is a gradual pas sage from true A. G. to others of a somewhat different character. Thus, there are glands called inguinal in the hare and rabbit—little bare places pouring out an unctuous secretion, which are held to be equivalent to A. G., only not inclosed in sacs. The civet cat has an anal sac on each side of the vent; and also two other sacs opening by a common outlet in front of the vent; and from the latter is derived the substance known as civet, which the negroes seek for on the trees where it has been left by the civet cats.
The civet gland furnishes a natural link between the A. G. and those more closely con nected with the genital apertures, called preputial. The most remarkable are those of the beaver, large sacs found both in the male and female, and which furnish the casto reum of commerce. The beaver has true A. G. besides. The sac which contains the musk of the musk-deer lies in the middle line beneath the skin of the abdomen, and opens at the prepuce. The secretion peculiar to badgers, polecats, and skunks, and which they use as an instrument of defense, shielding themselves from their adversaries by an overpowering and intolerable odor, comes from a pouch situated beneath the tail. In some animals, we meet with secretions similar to some of the above, poured out on other parts of the body. Thus, in the bat, there are glands on the face opening above the mouth, which prepare a fetid oily secretion; the so-called lacyrymal follicles of rumi nants, and the cutaneous glands of the tail of the deer, secrete a dark unctuous humor; and the temporal gland between the eye and the ear of the elephant pours out an oily substance at ruttingqime. The peccary has an odoriferous gland on its back; and the crocodile has a musk-sack under the lower jaw. Anal sacs opening immediately behind the vent are also found in the crocodile and in many serpents.