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Show 1903.] NEW SPECIES OF EARTHWORMS. 221 shape of the whole spermatophore is sufficiently elucidated by the drawing referred to. § Note on the Clitellum of Alma stulilmanni, and on a possibly new species of the genus Alma. I believe that a note by myself 1 upon the clitellum and spermatophores of a West-African species of the genus Alma is the first record of the extent of the clitellum in that genus. Like other aquatic forms, Alma seems to be characterised by a seasonal development of the clitellum ; and hitherto, with the exception just mentioned, no one appears to have seen or at least described this organ in that Geoscolecid. In the species to which 1 have just referred, the clitellum was found to extend from segment xlv. to lxxxv., a position which is quite unlike that found in any other Geoscolecid and present only in a few Lumbricids. This is an additional reason for associating the genus Alma more particularly with Criodrilus, as is done by Michaelsen ; for both these genera, though referable to the family Geoscolecidae, have many points of kinship to the Lumbricidse. As, however, up to the present time, but one species of the genus Alma has been described in the fully mature condition, it is possible that the position and extent of the clitellum characterising that species are not normal but exceptional in the genus. Therefore I do not hesitate to describe the conditions occurring in a second species of the genus, which I owe to the kindness of Mr. Cyril Crossland, who collected specimens on the shore of Victoria Nyanza, among weeds cast up by the waves. I have two fully mature examples of a species which I believe to be identical with Dr. Michaelsen's Alma stuhlmanni. The dimensions, however, are rather less; only one of the two examples was quite intact -the other had lost the hinder end of the body ; in the complete example, measurements showed a length of 120 mm. The other might have been slightly longer, as it was rather thicker. In both, the penial appendages were rather longer than those of the original specimens described by Michaelsen. I found them to be 10 millimetres long; in one example the two were unequal in size, one penial appendage only measured 6 mm. The structure of these appendages is usually characteristic of the species. The worms which I have examined agreed in almost every detail with the description of A. stuhlmanni as given by Michaelsen 2. I may remark, however, that there were only two seta? at the free end of the penial process, and, indeed, one of these had dropped out. The two papillae upon which these setae are placed were partly encircled by a horseshoe-shaped region of specially olandular epidermis, which was conspicuously marked out from the rest of the integument covering that process. It is conceivably this region which secretes the spermatophore. In addition to this, 1 " On the Clitellum and Spermatophores of an Annelid of the Genus Alma" Proc. Zool. Soc. 1901, vol. i. p. 215. 2 " Die Regemviirmer Ost-Afrikas," in Deutsch-Ost-Afnka, 1896, p. 4. |
