1S87.] ANATUMY OF EARTHWORMS. 379 



brought about. Tlie adult structure of the supposed ovary of 

 segment 14 might otherwise he regarded as an exaggeration of tlie 

 partial continuity of tlie receptaculum ovorum and the oviduct which 

 exists in Lumbricus Ac' 



The continuity between the oviduct and the ovary is a fact of 

 some little importance in the comparative morphology of Annelids. 

 In no other form that I am aware of is there a similar connection 

 between the gland and its duct, the two being invariably separate. 

 Tiiere is tlierefore a difference between Eudrilns and other Lumbri- 

 cidse, like that «liith exists between Lepidosteus and many Tele- 

 osteans on the one hand, and Osmerus and Amia on the other ^. It 

 may also be remarked that, at any rate in tliis particular, it is 

 impossible to draw a hard-and-fast line between the Hirudinea and 

 Annelida ; hitherto the Hirudinea have been regarded as differing 

 from Annelids in the possession of what have been termed "tubular 

 ovaries," where the duct "as suppo-ed to be an outgrowth or con- 

 tinuation of the gland itself. Recently Nnssbaum'^ has stated that 

 the reproductive organs in certain Hirudinea are developed indepen- 

 dently of their ducts, which have a resemblance to nephridia. 



It is plain therefore that in tliis case, at any rate, the distinction 

 betwee:i tubular and other ovaries falls to the ground. It is inter- 

 esting to note that the condition which is characteristic of the Leech 

 may also occur in a Chaetopod. 



Male Generative Apparatus. — In spite of tlie fact that Hering * 

 clearly demonstrated the true testes of Lumbricus, and distinguislied 

 them from the vesiculse seminales, the latter structures have until 

 very lately been called "testes." The rediscovery by Prof. Bourne^ 

 of the testes of the common Earthworm, and a number of subsequent 

 researche-!, particularly those of Dr. R. S. Bergh ", have fiimly estab- 

 lished the exactness of Bering's statements. With regard to exotic 

 genera of Lumbricidse, hov^ever, our knowledge is still very imperfect. 

 The fact that the so-called "testes" are, in the majority of forms, 

 apparently unconnected with the funnels of the vasa deferentia, and 

 the frequently racemose structure of the former bodies, has probably 

 influenced those writers who have (in my opinion erroneously) de- 

 scribed the vesiculse seminales as " testes." Dr. Horst appears to be 

 the first who has noticed the true testes in any post-clitellian or intia- 

 clitellian Earthworms ; in his account of the anatomy of Perichctta 



' It is quite impossible to regard this body as a receptaculum, containing as 

 it does indifferent cells, unless it be admitted that the receptaculum coincides 

 in position with the ovary, as in the case of the testes and vesiculte ; in this 

 case the continuity of the duct and the sac which envelops the ovary will ha\e 

 to be regarded as secondaiy. I am quite disjjosed to regard this as a possible 

 view, but it does not affect the anatomical fact of the continuity of the o\ary 

 and its duet in the adult condition. 



^ " Contributions to Morphology. Ichthyopsida. — No. 2. On the Oviducts of 

 Oamerun \ with Remarks on the Relations of tlie Telcostean w ith the Ganoid 

 Fishes," P. Z. S. 1883, p. 132. 



^ Zool. Aiizeig. Bd. viii. p. 181. 



* Zeitschr. f. wiss. Zool. Bd. viii. (1852). 



^ Quoted by J. E. Bloomfield, Quart. Jouni. Micr. Sei. 1880. 



'^ ZeitBchr.'f. wisa. Zool. 188fi ; Zool. Anzeig. i88r>, p. 231. 



