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Show 1886.] LITTLE-KNOWN EARTHWORMS. 313 generative orifices is certainly shown by the series of variations in Perionyx described in the present paper. When the male generative pores, as in var. no. 1, are placed very far forward, the clitellum also moves forward; on the other hand, when the male generative pores are situated further back, e. g. in segment 19, the clitellum likewise changes its position and occupies segments 15-18. In both these instances it will be noted that the relations of the male pore to the clitellum remain the same, although both structures have shifted their position ; in both cases, as in the normal condition, the male generative pore occupies the first segment after the clitellum. This fact would at first sight appear to be a strong argument in favour of Perrier's scheme of classification ; but in the first place the clitellum extends in var. No. 1 on to the left half of segment 16, and in the second place one variety (No. 3) was distinctly ' intraclitellian,' through the shifting forward of the generative pores on to the 17th segment. Ovaries and Oviducts.-I have been able to prove by dissection that the presence of two pairs of oviducts in consecutive segments is a reality ; the two oviducts of each side were quite obvious and were each furnished with their own ovary. Moreover in var. No. 11 there was an additional (third) ovary in segment 11, on the right-hand side. In var. No. 10 I also noted three pairs of ovaries. The occasional occurrence of more than a single pair of ovaries in this Earthworm lends additional support to my identification in Acanthodrilus of certain glandular structures with rudimentary ovaries, and also to Prof. Lankester's description in Cha?togaster of two pairs of ovaries, which has been recently doubted by Vejdovsky1. In the present instance there can be no doubt of the presence occasionally of two or three pairs of ovaries, since they were extremely conspicuous on account of their large size, and contained abundant mature ova. In two varieties (No. 5) there were only a single pair of ovaries present, but with separate openings on to the exterior. I have already in the present paper (p. 301, note) referred to the fact that this variation also occurs in Megascolex. Spermathecce.-The number and position of the spermathecae have been so constantly made use of as a systematic character, that it is well to emphasize their variations in the present species. They vary from two to four pairs, and may be placed in any of segments 6-11. In most cases they get to be placed further forward when the male generative pores shift their positions forward, but this relation is by no means constant. The occasional symmetry of these organs (e. g. in var. No. 12 and 13) cannot be a matter of any importance ; it was only observed in two of the four specimens. Male Generative Pores.-The position of these pores varies from segment 14-21, but they were invariably behind the female generative pores ; there was particular relation between the positions of the male and female pores, except that the latter were always in front of the former. 1 System u. Morph. d. Oligochaiten, p. l4o. PROC. ZOOL. Soc-1886, No. XXI, 21 |