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Show 1885.] NEW-ZEALAND EARTHWORMS. 817 § Alimentarg Canal. The alimentary tract of Acanthodrilus, as of other Earthworms, consists of a straight tube passing from the ventrally placed mouth at the anterior extremity to the terminal anus ; it is specialized into several distinct regions. The buccal cavity passes almost immediately into a large wide pharynx, which is attached to the body-wall by a mass of muscular bundles of various thickness ; in the pharyngeal region the mesenteries, which posteriorly limit the segments, are no longer recognizable, but have become metamorphosed into this mass of muscles. In A. dissimilis, and probably also in A. nova zelandia, a quantity of glandular tissue lies on the dorsal surface of the pharynx between the muscular fibres, which, no doubt, represents a salivary gland such as that which Perrier has described in Pontodrilus. I have been unable, however, to make out the ducts of these glands. In A. multiporus there are also salivary glands, which I am inclined to think are morphologically different from those of A. dissimilis. At the sides of the pharynx in segment 4 (Plate LI 11. fig. 4, gl) are a pair of large arborescent glandular masses ; the tubules which compose the gland of either side unite to form a slender duct (d), which is accompanied by a blood-vessel giving off capillaries which ramify over its walls. I traced the duct as far forward as the circum-cesophageal commissure ; at this point it passed under the commissure to open out the buccal cavity by a very conspicuous orifice (see fig. 5, o). The three anterior segments of the body occupied by this pair of glands and their ducts have no nephridia; and as the structure of these glands resembles exactly that of the nephridia, there is little doubt that they are the slightly modified representatives of the nephridia of these segments ; the most anterior nephridia were in the fourth segment, i. e. the third in front of that which contains the most anterior pair of copulatory pouches. Each gland consists of a multitude ofcsecal (?) tubes accompanied by an abundant supply of capillaries. Distally, the gland-tubules consist of rows of perforated cell quite similar to those of the distal section of the nephridia in Lumbricus &c. ; this portion of the tubule forms a complicated coil. Where the tubules unite together the character of the epithelium changes, and the duct comes to be surrounded by a row of cells instead of being contained within the substance of the cell. As the glands open into the buccal cavity, the}' may be termed salivary glands ; they appear to correspond to the " glande a mucosite" described by Perrier in the genus TJrocha-ta': there are two of these glands situated in the anterior region of the body, each opening by its own duct on to the exterior in the third segment. Like the salivary glands of Acanthodrilus, the mucous glands of Urochata have precisely the same structure as the nephridia ; and the fact that the latter are wanting in those segments of the body which contain the glands and their ducts is au additional argument for supposing, as 1 Arch, de Zool. Exp. t. iii. p. 439, pi. xvi. figs. 35, 37, 43. |