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Show 1892.] OF T H E G E N U S PERICHCETA. 157 PERICHCETA DYERI, n. sp. I obtained a single specimen of this Perichceta from Kew Gardens in August of last year ; Mr. Crisp, one of the employes at the Royal Gardens, brought me the worm, which had been remarked for some days on account of its active habits ; it had obviously come from some foreign country, but at that season so many plants in Wardian cases arrive from abroad that I found it impossible to ascertain its exact locality. The colour of this species when alive (Plate IX. fig. 2) is a rich brown, darker posteriorly; the cuticle is markedly iridescent, the iridescence being probably more strongly marked on account of the dark background of pigment. During life it protruded, as other Perichcetce do, the whole of the buccal cavity during its movements ; the clitellar region was also continually contracted: in preserved specimens this region of the body is, it should be observed, frequently much narrower than the rest; the older term of cingulum is thus particularly applicable, as the impression given is that of a belt tightly drawn round the middle of the worm. When placed in weak spirit, the worm threw out a quantity of turbid yellowish fluid. After preservation the specimen measured 117 m m . and was composed of 72 segments. The circumference of the body in the region of the spermathecae is 13 m m. The clitellum occupies the three usual segments, but does not exactly coincide with the boundaries of those segments ; it commences a little after the beginning of the xivth segment and terminates a little before the end of the xvith. There are no setae upon the clitellum. The seta formula is Segment I. V. XII. XXV.1 27 27 39 45 The oviducal pore is single and occupies the usual position. The male pores lie upon the xviiith segment withiu the line of setae, which are, however, interrupted for a short distance on either side of each pore. On the same segment are two pairs of large sucker-like papillce, which seem to have a concave surface. The anterior pair (Plate IX. fig. 8) lie in front, and to the inside, of the male pores ; the other pair occupy a corresponding position behind the circle of setae of the segment, and touch the border-line between the xviiith and xixth segments. The spermathecal pores were not evident. As to the internal anatomy. The alimentary tract is furnished with a gizzard occupying the usual position and number of segments. The paired cceca of the intestine arise between the xxvith and xxviith segments and reach forward as far as the xxvth. From segment xxviii. backward are paired series of " septal glands" 1 The segments selected for enumeration are not quite the same as those chosen by Prof. Eourne (Q. J. Micr. Sci. vol. xxxii. p. 53, footnote); but I find that the proportions and numbers are not altered by the segments which I give. |
