1887. J ANATOMY OF EARTHWORMS. 'Ml 



greater portion tbriiis a tuft situated in the neighbourhood of tlie 

 ventral pair of set* (c), between these and the nerve-coid; the distal 

 extremity of the tuhuL' opens by the ordinary funnel-shaped aper- 

 ture (a) into the next segment in front. 



Tlie excretory tubule then vn ideas out, and forms a section (6) 

 which pre-ents a close structural agreement with tbat lettered (ci) in 

 my figures of the nephiidia of ^'^awnorfriVMs'; tbis opens into tbe distal 

 section of tlie organ (a) wliich runs paiallel witli tbe last ; its walls 

 appear to contain a few muscular fibres. A Jjistological account of 

 the several legions of the nephridium is deferred for the present. 



§ Generative Organs. 



Female Generative Apparatus. — I have investigated the structure 

 of tiie female geneiative organs by dissection as well as by means of 

 transverse and longitudinal sections through tbe legion of tlie body 

 which they occupy. The excellent state of preseivation of the spe- 

 cimens enables me to add some few fact> to those which 1 have 

 already published ^ concerning the anatomy of the female reproductive 

 organs. I have also been able to obseive some facts btaiing upon 

 tbe development of the ovarian ovum, but tiiese 1 projose to make 

 the subject of a separate paper. 



The main facts with respect to the anatomy of tlie female lepro- 

 ductive organs stated in my former papers, 1 am able to coiifirm 

 from the study of the present species. In E. sylvicola as in E. boyeri 

 (and probably in all other s|iecies) the ovary is lontinuous witii a 

 much-coiled duct with ciliated lining epithelium and muscular walls 

 (Plate XXXllI. fig. 12) ; tbis opens on to tbe exterior in common 

 with a large speimatheca, upon tbe duct of whiuli a small gland is 

 sessde. 



A dissection of the present species shows that the female repro- 

 ductive organs, although opening on to the exterior in the 14th 

 segment, occupy botli this and the 13th segment ; the mesentery 

 between the two segments is apparently absent. An examination of 

 a seiies of longitudinal sections sho«s that tbe mesentery is not 

 entirely aborted ; the large spermatleca lies in both segments, and 

 the mesentery dividing them is attached to the sides of the sperma- 

 theca; lower down (tee woodcut, fig. 1, p. 381) the mesentery, when 

 present, divides off the ovary, which lies in the 14th segment, from the 

 oviduct, the greater part ot vvhidi lies in the i3th segment, and fioin 

 the glandular diveiticulum of the speimatheca which lies in the same 

 segment {sp, fig. 1). Since the female generative aperture lies in the 

 14th segment as well as the ovary, it is clear that the oviduct, the 

 greater part of which lies in the 13th segment, must perforate the 

 intersegmental mesentery twice. 



It is clear from my sections that the relative positions of the ovaiy 

 and its duct are precisely the reverse of that which is indicated in 



' Woodcuts, figs. T), 6, P. Z. S. 1887 (pp. 160, 161). 



= Zool. Anzeiger, Bd. ix. p. 342 ; P. Z. S. 1886, p. 202 ; Proe. Eoy. Soc. Edinb. 

 no. 122, p. 6. 



