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Show 1892".] SPECIES OF EARTHWORMS. 687 occupy the same segments, but each has a small irregularly shaped diverticulum sessile upon the duct of the spermatotheca. Finally, the atria are much larger than they are described in Perionyx excavatus or than they are in the species which I here identify with Perrier's Perionyx excavatus; they are m u c h broken up into lobes and extend through three segments ; the duct, too, is longer and is contorted ; these glands in fact resemble very closely those of a typical Perichceta. Some years ago I briefly described a species of Perionyx from Akyab 1 to which I gave the name of Perionyx macintoshii; this species is admitted by Vaillant2, but not very heartily allowed by Rosa3. I have got two individuals of a large Perionyx which I believe are referable to the same species ; if so it is certainly a " good species." M y observations upon Perionyx macintoshii were made upon a single, not sexually mature, example; thev were therefore not quite conclusive as to the distinctness of the species, though the large size alone is, as it proves, a sufficient index of the species, when compared with the three others described here. The internal anatomy is more like that of the first species from Seebpore, which I propose to term Perionyx intermedius ; the last pair of commissural vessels are in the xiiith segment; the atria, however, are limited to a single segment, and the spermatothecae have no appendix. The principal differences concern the external characters ; this species has a more extensive clitellum, it reaches from the xiiith to the xixth segment, being thus longer by two segments than in the other species; the male pores have not, as I pointed out in m y earlier description of the species, the characteristic appearance of those of Perionyx excavatus; they are placed in a ventral area, but the two pores are not upon separate papillae. The four species of Perionyx referred to in this paper show certain very characteristic differences in the condition of the male pores and of the setae in their immediate neighbourhood, of which the following is an account. In Perionyx gruenewaldi the area upon which the atrial pores are borne is not, owing to the small size of the worm, very well marked when looked at through a lens. When this part of the body is submitted to a microscopic examination, the area is seen to be bounded by an obvious groove. The ordinary setae of this segment (the xviiith) do not extend on to this area except on one side of the body, where a single seta is inserted on to the outer edge of the area; as, however, a groove cuts off the tract of integument which bears this seta from the genital area, it might be held that the line between the genital area and the surrounding integument was indicated by this groove. There are four genital setae on each side which, although 1 " Note on some Earthworms from India," Ann. & Mag. Nat. Hist. ser. xii. p. 217 (1883). 2 Anneles in ' Suites a Buffon, p. 86. *" Pericheticli di Birmania," Ann. Mus. Civ. Genova, ser. 2 a, vol. vi. p. 157 . 46* |
