REPRODUCTIVE ORGANS 



363 



clitellum ; in a few forms, such as, for example, Acanthodrilus 

 sc// ni ardae, the spermathecae have bundles of similar chaetae in 

 their neighbourhood, often associated with glands not unlike the 

 spermiducal glands. 



In most, perhaps in all Oligochaeta the sperm is not matured 

 in the testes, or even in the body-cavity ; it is received into 

 special sacs which are called sperm-sacs, 

 and there ripens. These sacs, the vesi- 

 culae seminales, have been shown to be 

 outgrowths of the septa ; their cavity 

 is thus a portion of the body-cavity 

 shut off more or less completely from X!V 

 the general body-cavity. 



The reproductive organs of the 

 Eudrilidae, and particularly the female 

 organs, are so divergent in many par- xill 

 ticulars from those of other Oligochaeta 

 that it is convenient to treat them 

 separately. The testes are normal, save 

 that they are often adherent to the 

 posterior wall of their segment, as, how- 

 ever, is the case with some other earth- 

 worms. In many Eudrilidae, for in- 

 stance in the genus HyperiodrilllS, the Fig. 193. Female reproductive 



funnels of the sperm-ducts are dependent Xxv, "*%**, 

 from the anterior wall of the segment 



body ; 1, spermathecal sac : 

 2, egg-sac ; 3, spermatheca ; 

 4. ovarv. 



which contains them ; the narrow tube 

 which follows projects into the segment 



in front, and is there immediately dilated into a wide chamber, 

 which again narrows, and bending round, re-traverses the same 

 septum ; the two ducts of each side (if there are two, which is 

 not invariably the case) remain separate and open separately 

 into the glandular part of the spermiducal gland. There is 

 occasionally only a single median gland ; and as a general rule 

 the two glands open by a median unpaired orifice. Tenia 1 chaetae 

 may or may not be present. 



The structure of the female organs diti*. is considerably in 

 detail in the different genera. But Hyftriodriluk may be taken 

 as an instance of a genus in which these organs are as compli- 

 cated as they are anywhere. The ovaries (Pig. 193, 4 are 



