The Classification and Distrihution of Earthworms. 243 



(5.) One pair of oviducts opening internally into the xiii//<, 



externally on to the xiwth segment. 

 (6.) One pair {rarely two, as in Perichseta aspergillum) of 



egg sacs, minute bodies in segment xiv. 



Branch B. Moniligastres. 



(1.) One j^air of testes in ix. or x. 



(2.) One pair of sperm sacs in segment x., with simple undi- 

 vided cavity. 



(3.) Vasa deferentia, one pair opening into ixth or xth 

 segment (according to jjosition of testes) internally, and 

 on to intersegmental groove between x.-xi. externally, 

 by an ati^ium like that of the Lumbriculidce. 



(4.) One p)air of ovaries in segment xi. (1). 



(5.) One pair of oviducts opening behind the atrial pores 

 into segment xi. 



(6.) Egg sacs large, extending through several segments. 



It seems to me impossible to regard these two groups as 

 resembling each other so much more closely than either of 

 them resembles any given group of the " Limicolse " as to 

 necessitate their inclusion in the same group. I do not, 

 however, think it worth while to recapitulate more fully than 

 in the above table my reasons for this belief, as I have 

 already discussed the matter in the papers referred to in the 

 footnote.^ 



Arch, de Zool. Exp., t. i., 1872), the ducts have been stated to open on to the 

 xth segment. 



In Brachydrilus Benham has stated (Note on a New Earthworm — Zool. 

 Anz., Bd. xi., No. 271) that the ovaries lie in segment xii. — "an unusual 

 position." It is, if no more, a curious coincidence that this should agree 

 exactly with the positicm of the ovaries in Microchccia Haj^pii, as determined 

 by Benham (Studies on Earthworms, No. 1 — Q. J. M. S., vol. xxvi., p. 279) 

 and myself (On the Anatomy and Systematic Position of a Gigantic Earth- 

 worm [Microchceta Rappii] from the Cape Colony — Trans. Zool. Soc. , vol. xii., 

 p. 75), seeing that these genera are allied in other particulars. It is true 

 that both Benham and I myself gave xiii. as the ovarian segment. I myself, 

 however, pointed out later (Descriptions of some new or little known 

 Earthworms, etc. — P. Z. S., 1886, p. 306) that the organ described by us as 

 "ovary" was probably " receptaculum ovorum " — the ovary really lying in 

 segment xii. I have again looked into the matter, and can confirm the 

 above statements with regard to position of ovaries, etc. 



^ For fuller details respecting Moniligastcr, see my paper On the Struc- 

 ture of a Genus of Oligochseta belonging to the Limicoline Section — Trans. 

 Roy. Soc. Edin. , vol. xxxv. , and the literature therein cited. 



