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Show 36 MR. F. E. BEDDARD ON EARTHWORMS [Jan. 5, paper \ surmised that Fletcher's2 Eudrilus dubius would prove to be a Microscolex. This suggestion was later3 shown to be correct by the description of a species of Microscolex evidently identical with Eudrilus dubius from the Argentine. I received myself, some time since, a number of examples of a Microscolex from Madeira, through the kindness of Mr. E. B. Poulton, F.R.S., which are described above. The existing knowledge of the distribution of the genus is as follows:- 1. Microscolex modestus. Italy, Argentina. 2. Microscolex dubius. Australia, Argentina. 3. Microscolex algeriensis. Algiers. 4. Microscolex poultoni. Madeira. The characters of M. algeriensis evidently necessitate a revision of Rosa's generic definition given on p. 511 (3 of sep. copy) of his memoir on the Argentine Earthworms. The following points are, I think, sufficient to distinguish this genus from any other genera among the Cryptodrilidae. Genus MICROSCOLEX, Rosa. Microscolex, Rosa, Boll. Mus. Zool. Torino, vol. ii. no. 19. Seles 8 per segment, distant. Clitellum on segments xiii., xiv., xv., xvi., xvii., complete. 3 pores on xvii. No dorsal pores. Subnervian vessel absent. Nephridia paired, present in genital segments. Hearts, 3 pairs in segments x., xi., xii. Gitzard absent or rudimentary. Intestine without typhlosole. Atria tubular, with or without penial setce. Spermatotheca {if present) one pair in ix., with diverticulum. The affinities of the genus have been discussed by Rosa, who compares Microscolex with Photodrilus and Pontodrilus. I may point out that the absence of penial setae in Microscolex algeriensis lessens the distance between the genus and Pontodrilus. The species which I describe here is quite clearly distinct from the two others. The table (on p. 37) indicates the principal resemblances and differences between the four species Microscolex dubius, M. modestus, M. algeriensis, and M. poultoni. 1 " Sui generi Pontodrilus, Microscolex, e Photodrilus," I. c. vol. iii. no. 39. 2 " Notes on Australian Earthworms," pt. iii., Proc. Linn. Soc. N.S.W. vol. ii. ser. 2. 8 "I terricoli Argentini raccolti dal Dott. Carlo Spegazzini," Ann. Mus. Civ. Genova, vol. ix. ser. 2. |
