THE ANATOMY. SPERMIDUCAL GLANDS 105 



funnels is also not without its analogies ; particularly among the Protozoa where 

 the vanishing of cilia so far from being an indication of degeneration is actually 

 the prelude of renewed activity. In any case the facts appear to be as stated in 

 Octochaetus. Another point to be emphasized in connexion with the development 

 of the genital-ducts is their early appearance in Octochaetus as compared with 

 Lumhricus. The facts which I have made out as to the development of the genital 

 ducts in Octochaetus appear to absolutely contradict the facts established for Lumhricus 

 — so much so, indeed, that it seems hardly credible that both can be correct. A little 

 consideration, however, I think shows that there is not necessarily any contradiction. 

 In Lumhricus the ducts appear after the nephridia have acquired their definite form ; 

 there is every reason, therefore, why they should not show any actual connexion 

 with them in development, since presuming their homology with the genital ducts 

 of Octochaetus the latter are formed out of the remains of a part of the pronephridia. 

 The genital ducts of Lumhricus are formed so late that they cannot be produced out 

 of the pronephridia which have been in the meantime converted into the nephridia. 

 Another point to be observed is that in Octochaetus the polynephric condition is to 

 some extent established before the commencing differentiation of the sperm and 

 oviducts. It is possible therefore to regard the existence of both in the same segment 

 in Lumhricus as the last remnant of an ancestral condition where the nephridia were 

 numerous in each segment. 



As tending to prove that in some ' meganephric ' worms at any rate the funnels 

 of the genital-ducts are formed out of the funnels of the pronephridia I may say 

 that I could find no nephridial funnel in the tenth, eleventh, and thirteenth segments 

 of Alvania millsoni, but I did find them in the fifth to ninth and in the twelfth and 

 fourteenth segments. In GordiodrUus there were none in the thirteenth at any rate. 



§ 7. Spermiducai Glands^. 



In some Oligochaeta the sperm-ducts open on to the exterior directly; in others, 

 and these are the majority, the sperm-ducts open into a wide terminal chamber 

 which itself opens exteriorly; this is the case with the LumbricuUdae, the Tubificidae, 

 the Perichaetidae, many Cryptodrihdae, the EudriUdae, the Naidomorpha, the Chaeto- 

 gastridae, the Moniligastridae, the Enchytraeidae ; in a limited number of genera of 

 Cryptodrilidae and in all the Acanthodrilidae there are these glands, but the sperm- 

 ducts open separately on to the exterior though in their immediate neighbourhood. 



1 I prefer this name, recently suggested by myself (80) to either atrium or prostate as it emphasizes 

 the position and relation of the glands, and having been never used before has no preconceived meaning 

 attached to it. 



P 



