352 MB. F. E, BEDDARD OlS EARTHWORMS [Apr. 16, 



Michaelseu \ which I am able to confirm, there remain one or two 

 points, in addition to the structnre of the spermatophores, which 

 he has not treated of so eshanstively. It is to these that I desire 

 to call attention in the present communication. 



I have pointed out myself that there is often in the species 

 S. variabilis ', to which my present observations appear to apply, 

 a curious asymmetry of the reproductive organs resulting in the 

 entire disappearance of one of the two receptacula_ ovorum. The 

 same asymmetry in examples which I have examined by micro- 

 scopical sections has involved the ovary, there being in at least one 

 specimen but a single ovary which corresponds to the receptaculum 

 ovorum, both being those of the left side. The ovary itself 1 

 have succeeded in finding. 



Michaelsen's description does not exactly apply to these gouads 

 in the worms which I have examined. His account of the 

 matter, translated, is as follows : — " From the bottom of the sacs 

 [which enwrap the intestine] stretch out small lobulated cell- 

 masses into the lumen of the tubes. These cell-masses stain in 

 picrocarmine with more intensity than the epithelium cells of the 

 walls [of the tube], and can only be regarded as ovaries. This 

 interpretation is supported, apart from their appearance, by their 

 position. The wide atrium extends beyond the level of its external 

 opening forwards, and the point of origin of the two sacs lies 

 anteriorly in the thirteenth segment ; thus the cell-masses con- 

 tained in it lie in the position where the ovaries are normally found 

 among earthworms." There is no suggestion that Michaelsen's 

 second species of Stuhlmannia, viz. >S. gracilis, differs from the 

 tvpe species in this point. 



JNow I find that the single ovary — I found but one, as already 

 stated — is contained in a special forward diverticulum of the 

 terminal atrium of the female spermathecal system, which is in 

 connexion with the two sacs which surround the gut, but is quite 

 distinct from them as a special outgrowtli of the complex system 

 of sacs which constitutes in this worm the spermathecal sac. 

 This small forward diverticulum nearly, but not quite, touches 

 the septum dividing the two segments xii./xiii. At the very end 

 the walls of the sac are slightly imperfect so that the tissue 

 of the base of the ovary is there free ; it is not, however, in contact 

 with the septum. The appearances suggest that the ovary has 

 been, so to speak, forcibly torn away from the septal wall by the 

 growth of the sac which has surrounded it. It is important to 

 notice the distinctness of the ovarian sac from the rest of the 

 spermathecal apparatus, since in Eudrilus and in other forms a 

 longish duct intervenes between the sac which contains the ovary 

 and the external orifice of the spermathecal sac. The ovarian 



^ " Besclireibuiig der vou Ilerrn Dr. Fr. Stuhlmami auf Sausibar uud deai 

 gegeniiberliegenden Festlande gesammelten Terricolen," JB. Hamb. wiss. Anst. 

 ix. ; and " Die Eegenwiirmer Ost-Afrikas," in Deiitseh-Ost-Afrika, iv. p. 23. 



- A Monograph of the Ohgochata, Oxford, 1895. It must venifiin for the 

 present uncertain whether this species is really 'S'. variahiJh, 



