252 FRANK E. BEDDARD. 



Teleudrilus will bear reinvestigating from this point of view. 

 The two tubes which are described by Rosa (10) as diverti- 

 cula of the sperm atheca have a certain likeness to the narrow 

 coelomic sac of Hyperiodrilus, which puts into communica- 

 tion the ovarian sacs and the space surrounding the sperma- 

 theca; and they approach each other in the middle line, which 

 suggests the possibility of their being really fused. 



The mature ova have the characters illustrated in fig. 49. 

 The most remarkable feature is a thick, darkly staining mem- 

 brane, which completely surrounds the ovum ; this membrane 

 is traversed by numerous pores. 



I have described something of the same kind in Eudrilus 

 (2), where, however, it forms a cap at one end only of the ovum. 

 After examining Hyperiodrilus it seemed possible that I 

 was mistaken in considering that the membrane in question 

 was limited to half of the ovum in Eudrilus. I cannot, how- 

 ever, find that I have made any mistake in this matter in my 

 description of Eudrilus.^ This being so, it does not seem very 

 likely that the cap of darkly staining cubical bodies which 

 cover one pole of the ovum in Eudrilus are comparable to a 

 radiately striated egg-membrane ; such a membrane would 

 surely be produced round the whole of the periphery of the 

 ovum at once. There are, therefore, still reasons for adhering 

 to the opinion which I expressed in the paper dealing with the 

 structure of that ovum, viz. that the columnar layer is in reality 

 a product of tlie follicular cells, being formed by the metamor- 

 phosis of a certain number of them. This opinion is considered 

 by Vejdovsky (12) to be probably true. 



The resemblance between this structure in Eudrilus and 

 the complete membrane which surrounds the ovum of 

 Hyperiodrilus is close; but I do not feel sure that they 

 actually correspond ; a membrane surrounding one half of the 

 ovum seems to be exceedingly anomalous. The ova within 



^ My descriptiou lias been confirmed in a paper by Dr. Horst which I 

 received after the present memoir was sent to Professor Lankester, " Sur 

 quelques Lombriciens exotiqucs apparteuant au j^eurc Eudrilus," ' Mem. See. 

 Zool. de IVance,' t. iii, p. 223 (cf. fig. 11 of plate). 



