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Show 354 MR. F. E. BEDDARD O N [May 3, each of the ventral bundles. The number of setae per bundle diminishes in the posterior segments, and they become mingled with sigmoid setae. In the seventh segment both setae in one of the ventral bundles were sigmoid, as was one of the two setae of the dorsal bundle. The sigmoid setae occur, therefore, in both dorsal and ventral bundles ; I was, however, quite unable to detect any bifurcation at the free extremity of these setae, and I examined them with the highest power at m y disposal (Zeiss's F lens with eyepiece). I could not detect the nephridia. In the colourless integument and in the presence of two kinds of setae this species evidently offers a transition to the Naidomorpha. iv. On Clitellio and Limnodrilus. These two genera, usually regarded as distinct, have been united by M . Vaillant in the recently published third volume of the 'Anneles ' in the ' Suites a, Buffon.' M . Vaillant considers that the alleged absence of a prostate in Clitellio is not a sufficient difference. As a matter of fact, m y own paper1 upon Clitellio showed other points of difference besides the absence of the prostate; the main distinction between the two genera, in addition to the want of a prostate, is the existence of two pairs of perivisceral trunks, which are specially enlarged and are contractile: I did not refer very definitely to their contractility in the paper cited, but I have since reexamined the species Clitellio arenarius and find that these dilated trucks are contractile, one pair contracting before the other. Now the fact of the existence of contractile trunks does not distinguish Clitellio from Limnodrilus. Limnodrilus has also two pairs of contractile periviscerals, but only one pair of these are dilated ; whereas in Clitellio both pairs are wide tubes. This difference, at any rate, applies to the species of Limnodrilus known up to the present. I take this opportunity of mentioning that Clitellio arenarius has, like Limnodrilus, a supra-intestinal blood-vessel. But I could find no integumental blood-capillaries such as are found in Limnodrilus. I looked for them very carefully, of course in living worms. So far, therefore, m y observations have rather tended to accentuate than remove the differences between Clitellio and Limnodrilus. I have, however, found in a species of Limnodrilus an intermediate form between Clitellio and the typical Limnodrilus. This species is from N e w Zealand ; I have already a recorded its occurrence iii the South Island, though I was in error in stating that it presented no differences from the European species. As a matter of fact, this N e w Zealand Limnodrilus has, like Clitellio, two pairs of greatly dilated hearts in segments viii. and ix.; there are no reasons for disbelieving that these wide trunks are 1 " On certain Points in the Structure of Clitellio (Olaparede)," P. Z. S. 1888, p. 485. 2 "On the OligochEetous Fauna of N e w Zealand, &c.," P.Z.S. 1889, p. 381. |