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these organs behind the testes are against such an identification; at 
the same time, in Microchcetct , Mr Benham* and myself f have de- 
scribed a number of small pouches, which may correspond to the 
spermatheca, and are in a similar position as far as the testes are 
concerned. Furthermore, the position of th.e conjoined oviduct and 
spermathecal apertures by the outer pair of setse, while the male 
genital pores are placed on a level with the lowermost pair of setae, 
suggests a practical difficulty in assigning to these pouches the 
function of seminal reservoirs. I have not succeeded in finding 
any trace of spermatozoa within the supposed spermatheca ; hut this 
failure does not count for much, considering the condition of the 
specimens. In my opinion, the nature of these so-called sperma- 
theca must he left undecided for the present; they appear to he 
possibly new structures developed on the oviduct, hut probably 
serve as spermathecae. 
(2) The absolute continuity between the ovary and its duct is not 
merely new to the Oligochceta terricola , but to the whole of the 
Chaetopoda. In this group the generative ducts are more generally 
regarded! as the slightly metamorphosed equivalent of nephridia; 
and, without insisting upon their homology with nephridia, it is at 
any rate clear that they are quite independent of the generative 
glands, both as regards origin and adult structure; in other groups 
of the invertebrata there is some dispute as to the nature of the 
genital ducts. Lang§ speaks of the sexual products in the Platy- 
helminthes and Hirudinege being carried off* by special ducts, which 
are prolongations of the genital ducfs themselves. Balfour || considers 
this view doubtful in the case of the Hirudineae and Platyhel- 
minthes, but is in favour of regarding the genital ducts of the 
Nematodes as being of this kind. In all these instances, as well 
as in the Crustacea and in some Mollusca (and, according to the 
Hertwigs,1T in Bryozoa and Rotifera), the genital products are carried 
out of the body by ducts which, whether they are or are not modi- 
* Quart. Jour. Micr. Sci. , March 1886. 
t Trans. Zool. Soc ., vol. xii. part 3. 
+ Balfour, Comparative Embryology, vol. ii. p. 618; Gegenbaur, Elements of 
Comparative Anatomy]; Huxley, Anatomy of Invertebrated Animals ; Lankes- 
ter, Ency. Brit., art. “Mollusca.” 
§ Arch. d. Biol., vol. ii. (1881), p. 551. 
|| Comp. Embry., vol. ii. p. 619. 
IT Coelomtheorie, p. 26 et passim. 
