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Show 1903.] OLIGOCHiETA FROM NEW ZEALAND. 217 Sperm-sacs occupy segments xii., xiii., and eggs lie free in segments xiv., xv. The chitinous penis is about ten times as long as the breadth of its base (PI. X X V . fig. 18); it is distinctly bent at a point just below its outer end, and terminates in an asymmetrical, somewhat trumpet-mouthed expansion, which is apparently imperfect on one side, as the chitin here becomes very thin (PI. X X V . figs. 19, 20); there appears to be a "valve-like" arrangement, somewhat like that figured by Vejdovsky for L. claparedianus (pi. xi. figs. 7, 8). The muscles surrounding the penis are spirally wound. The spermatheca (PI. X X V . fig. 21) has an irregularly pyriform ampulla, connected to the pore by a narrow neck passing into a short muscular duct, which is rather wider in the middle of its course than at either end. The duct is much shorter than in the previous species. The spermatophores (PI. X X V . fig. 22), which I observed in one instance, are dumbbell-shaped-i. e., an oval constriction round its shorter diameter. Bimensions. Length 15-35 mm.; diameter | m m . or \ m m. With 60 to 80 segments. Localities. Lakes Rotoiti and Taupo, North Island, N e w Zealand. Obtained in considerable numbers at both places. Remarks.-This worm is much more slender than L. vejdovskyanus, and, like it, differs from the majority of species of Limnodrilus in possessing no integumental vessels, so far as can be made out in preserved specimens. As the blood was distinct enough in the intestinal network, it seems unlikely that I overlooked the vessels on the body-wall, or going thereto. It appears to approach L. dugesi Rybka*, from Mexico, from the diagnosis given by Michaelsen; but I have not access to the original paper in which it is described. LIMNODRILUS sp. inc. From Lakes Wakatipa, Manapouri, and Waikaremoana some immature specimens were obtained to which I will not give a specific name, but which differ from either of the preceding species. The chaetae are in bundles of 4 or 5 anteriorly, but soon decrease to a couple: or in some instances (the single individual from the southern lake) the maximum, anteriorly, is two per bundle, and posteriorly, both dorsally and ventrally, a single cheta. But in both cases the form of the crochet is the same ; the upper prong is much larger than the lower, indeed as much as twice the length, and is much more slender and more elegantly curved, as it seems, than in the preceding species ; the lower tooth is slightly stouter than the upper. A more important difference from the preceding species is the possession of two pairs of swollen hearts in segments viii. and ix. In one case, although only the rudiments of the generative organs are present, the epidermis is slightly, but definitely, thickened on segments 5 x., xi., \ xii. * Rybka, Mem. Soc. Zool. France, xi. p. 380. |
