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first described by d’Udekem,* tire discoverer of these organs ; this 
structure, which is a prolongation of the delicate cellular covering of 
the ovary, was erroneously regarded by d’Udekem as the oviduct; 
it may possibly represent morphologically the oviduct in Eudrilus , 
and be the last remnant of an oviduct continuous with the ovary, 
such as exists (?) in the unsegmented worms from which the Annelida 
must have originated. 
(3) The minute structure of the ovary in Eudrilus is evidently 
different from that of other Oligochaeta ; in Lumbricus f these 
glands are little more than a specially thickened region of the peri- 
toneal epithelium, enclosed in a thin capsule formed by the peri- 
pheral layer of cells. In Eudrilus the glands show a very con- 
siderable advance in structure; the details given above, although 
unfortunately very imperfect, seem to indicate that the ovaries may 
have originated, not from the epithelium lining the general body 
cavity, but that they may more nearly resemble the ovaries of the 
Platyhelminthes and Leeches, which belong to the “ tubular” type. 
This question can, of course, only be settled by a study of their 
development. In the case of the Leeches, Balfour supposes, that 
“ if, as seems probable, the true affinities of the Leeches are with 
the Chsetopoda, the investment of the ovaries must be of a secondary 
nature.” Very possibly this is also the case with Eudrilus , but in 
the meantime the structural resemblance to the Leech is a fact to be 
noted ; in both cases the ovary is enclosed in a muscular coat. It 
might be objected to what I have already said, that in the ovaries and 
oviducts of Eudrilus there is a similarity to the testes and vesiculse 
seminales of earthworms. These organs, as we know from the 
researches of Hering,j: confirmed by Bourne, § have the following 
structure: — There are two pairs of minute testes about the same 
size as, and occupying a similar position to, the ovaries. The con- 
tents of the testes are transferred, when in a more or less complete 
condition, to pouch-like structures, developed at the expense of the 
proximal ends of the vasa deferentia, or according to Bergh ( Zool . 
Anzeig ., Bd. ix. p. 232) from the septa. These seminal vesicles are 
* Mem. coior. et mem. d. savants drag . , Acad. Roy. d. Belgique, t. xxvii. 
(1856), p. 20. 
+ Claparede, Zeitschr. f. wiss. Zool., Bd. xix. (1869). 
t Zeitschr. f. wiss. Zool., (1852). 
§ Quoted by Bloomfield, Quart. Jour. Micr. Sci., vol. xx. (1880). 
