33 



is specially obvious in the segments, containing the male genital 

 organs, while it is no more recognisable in the anterior body-region. 

 The longitudinal muscle-fascicle, in the median dorsal area of each 

 segment , considered by Ude a ) as the opening-muscle of the dorsal 

 pore, could be distinguished very clearly. I do not understand that 

 Cbrfontaine, who lately admirably worked out the histological struc- 

 ture of the body- wall of Lumbricus, makes no remark upon those 

 fascicle 2 ). 



The nephridia consist of a network of delicate tubules, spread 

 over the whole internal side of the body-wall, except on a narrow 

 median area at the ventral- and dorsal side. However there is some 

 difference in their arrangement in the anterior and the posterior seg- 

 ments of the body; for in the anterior body-region they line the 

 whole inner surface of the body-wall , whereas in the segments behind 

 the clitellum they are confined to four groups on each side. The three 

 external groups, having a roundish shape, are situated enternally to 

 the dorsal series of bristles; the fourth internal group, of a more 

 oblong shape, is for the greater part confined between the ventral 

 and dorsal series of bristles. 



The dorsal vessel is a single tube, which communicates with the 

 ventral trunc through five pairs of commissural vessels , of which the 

 posterior three are the largest. 



The pharynx is covered by a compact mass of glands, dividing 

 posteriorly in two symmetrical halfs. The gizzard lies in segment VI 

 and VII and consists of two divisions; its muscular wall being in- 

 terrupted by a narrow membranaceous interval. 



In segment XV, XVI and XVII the tubular intestine is provided 

 on each side with calciferous glands. 



There are two pairs of spermathecae in segments VIII and IX; 

 each of them consists of a tubular pouch, which is slightly curved 

 and terminates in an enlarged extremity (PL II. fig. 4). Below its 

 middle the spermatheca is furnished with a pyrifor m diverticulum, that 

 is filled with spermatozoa. 



As already pointed out by different authors, there exists some diffe- 

 rence in the minute structure of the different parts of the sperma- 



1) Zeitschrift f. wissens. Zoologie, Bd. XLIII, 1886, p. 87, pi. IV. 



2) Archives de Biologie, T. X, 1890, p. 327, pi. XI— XIV. 



