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Show 230 ME. F. E. BEDDABD ON NEW EAETHWOBMS. [Mar. 19, The length of a specimen selected for measurement was 40 mm. by 3 m m . in diameter. Number of segments 95. The prostomium is complete. Dorsal pores are visible. The clitellum occupies segments xiii.-xvii., and is not developed all round the body. There are no papillae of any kind that I could discover. The gizzard is in segment vi. The last heart is in xii. The sperm-sacs in xi. The sacs of penial setae are, as in Microscolex papillosus, of enormous length. They measure 6 m m . and extend through fourteen segments. The spermiducal glands, on the other hand, only extend through six segments. Tbe penial setae have the same form as in Microscolex papillosus. The spermathecae are also exactly as in that species. Hab. St. 193, Tierra del Euego, Puerto Pantalon; St. 187, Tierra del Euego ; St. 140, Uschuia; St. 178, Navarin, Porto Toro. (3) Microscolex papillosus, n. sp. Of this rather remarkable new form three individuals were taken in forest at Uschuia. The largest specimen measures 87 m m . ; its diameter is only 3 m m . ; the number of segments 95. The worm is thus a slender species. Like so many of the American species of Microscolex, it is pigmented ; but the pigmentation is not very great, the anterior end of the w o r m dorsally being alone much coloured. The colour is purplish. In one individual there was no pigment. Tbe setae are quite strictly paired. The prostomium is not continued by furrows over the entire buccal segment; it extends over about half of it. The clitellum occupies segments xiii.-xvi.; it is complete. O n the sixteenth segment in the middle line is a deep hole, looking as if caused by the contraction of the stout muscles connected •with it and passing to the dorsal parietes. This is very characteristic of the species, and was not confined to the largest individual which was selected for dissection. It lies in the clitellar region, but is lined by a strong tall epithelium, which is not glandular like that of the clitellum. There seem to be no dorsal pores. The genital papillae are very numerous, an unusual state of affairs in this genus. There are at least six of them round somewhat translucent areas, possibly rather sense-organs than glandular papillae, upon the middle of segments xii.-xii.; I am inclined to think that others were to be distinguished upon the clitellum. But I did not, with a view of preserving the specimen intact, submit this part of the body to a microscopical examination. In another specimen there was an additional papilla upon xiii., a smaller median papilla upon xv., and a pair upon xvi., one on either side of the median depression. The male pores upon segment xvii. are very prominent; each is |