1901.] ANiifEtiD OP *HE C^BNtJS AtMA. 217 



to be usually the case with full-grown terrestrial forms. And in 

 this connection it should be borne in mind that Ahna is very 

 largely an aquatic genus itself. 



GUtellum. — TheGreoscoHcidse agree with theLumbricidse, to which 

 they are clearly very closely related, in the fact that the clitellum is 

 often placed very far back in the body. Such a position is especially 

 characteristic of the Madagascar genus Kynotus, in four species of 

 which the clitellum commences at the sixth to the xxist segment. 

 There is,, however, no Greosolecid where the clitellum commences 

 at a point farther back than the xxiind segment ; Glyphidrilus 

 stuhlmcmni has a clitellum which commences at this segment. On 

 the other hand, in the Lumbricidse the clitellum is as a rule much 

 farther back than in the Geoscolicidse, commencing as a rule at a 

 segment between xxii. and xxx. It is to this family that Alma shows 

 the greatest likeness. In the specimen before me the clitellum 

 (text-fig. 59, Gl.) is exceedingly plain on account of the white and 

 opaque appearance of the integument; the individual segments which 

 are comprised within the clitellum are, however, perfectly distinct, 

 their lines of division not having been obliterated by the glandular 

 modification of the skin. The clitellum does not commence or 

 end at all sharply. The first segment which is fully modified is 

 segment xlvii. ; but two or three segments in front of this are 

 slightly invaded by glandular tissue and in an irregular fashion. 

 It is possible therefore that in a more fully mature example the 

 clitellum would be found to have a greater extent than even 

 the very large one which I record here. The last segment of the 

 clitellum which is completely modified is segment Ixxxii. ; but here 

 again two or three segments after this one are slightly modified. 

 We may regard it as extending from xlv.-lxxxv. The clitellum, 

 where fully developed, is coutinuous right round the body. This 

 position of the clitellum is, however, much farther back than is 

 the case with the large majority of the Lumbricidee. There are, 

 indeed, only fom' species where it commences at or just before the 

 xlth segment. In Allolohoplwra robusta the clitellum extends from 

 xl.-lxii. ; in A. molleri from xlviii.-lix. ; in A. moebii from lii.-lxii. 

 Lumhricus polypliemus has a clitellum which reaches from xxxix.- 

 xliy. It will be observed therefore that Alma is very exceptional 

 in the backward position of this region of the integument, and 

 that in extent coupled with position it is quite unique among 

 earthworms. 



SpermatopJiores. — The existence of these structures can be 

 affirmed for the Lumbricidse and for Griodrilus and Polytoreutus 

 alone among the earthworms. As regards the former family, de 

 Eibaucourt has recently added so much to our knowledge of those 

 species among the genera Lumhricus and AUolobophora which possess 

 spermatophores (10), that his conclusion that their existence will 

 prove to be nearly if not quite universal for the family seems to 

 be reasonable. The spermatophores of Griodrilus are much like 

 those of the Lumbricidse. Those of Polytoreutus on the other hand, 

 described by myself, are of a different pattern, and on the whole 



