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Show 360 MR. F. E. BEDDARD ON EARTHWORMS [Apr. l('' prostomium is not cut off from the peristomial segment by any furrow. The setce present on the whole the characters of those of Gordiodrilus tenuis in that there is a difference in size between the ventral and the lateral pairs. The ventral pairs are much more marked than the lateral, especially in a few segments just anterior to those which bear the male generative orifices. In this situation they appear to tbe naked eye as strongish hooks. Five segments or so showed these particularly strong seta?. But an examination of the very last segments of the body showed a similar difference in size, only that here the difference was not so pronounced. The condition of the seta? of the present species is in some respects intermediate between that which characterizes Gordiodrilus tenuis aud G. robustus. In the latter species the ventral sette of a few segments in front of the male genital pores are markedly" larger than the rest. In G. tenuis, on the other band, the whole series of ventral seta? are much larger than the lateral, and their increased size can, as has been pointed out, be readily felt when the worm is handled. As in some other species of Gordiodrilus, the ventral seta? of the generative segments are partly absent. The clitellum is a little difficult to map on a naked-eye inspection of the worm. Segments xviii.-xxii. appeared to be those occupied by this modified region of the integument.1 The genital region of this species shows several characters which enable tbe species to be differentiated from all its allies. As will be seen by the accompanying figure (text-fig. 88, p. 359), the segments which carry the male pores are somewhat swollen when compared with those that immediately precede and succeed. On these two segments, which are the xviiith and the xixth, a somewhat figure-of- 8-shaped tumid area extends from end to end on each side ; this is traversed by a longitudinal groove; the whole area of each side measures 3'25 m m . and the groove about 1-8 mm. The swollen structure would seem to be capable of performing the function of a sucker. But iu addition to it there are four pairs oi genital papillce, the presence of which has suggested the name of the species, and which serve at once to differentiate Gordiodrilus papillatus from any of the other species of the genus which have beeu hitherto described. These papillae are arranged in pairs following each other. The first pair are iu front of the anterior end of the figure of 8. The last pair occupy a corresponding position behind this figure of 8, and in the middle are the two remaining pairs, closer together than either of them is to the first or to the last pair of papilla?. The groove which traverses the swollen sucker-like structure widens at both the anterior aud at the posterior end, and at these points open the spermiducal glands. After an interval of four segments there are three segments, each 1 I am indebted for the sketch from which the above drawing was made to Miss Fedarb. |
