340 



OLIGOCHAETA 



the doubtful species E. affinis. This resemblance to Pachydrilus is further increased 

 by the fact that the ventral nerve-chord has outgrowths such as those which occur 

 in P. nervosus (see p. 323), which are found in the first post-clitellian segments. The 

 nephridia are peculiar in the points mentioned in the definition; besides these, 

 MiCHAELSEN figures (fig. 5 c) a transparent sheath covering the dorsal aspect of the 

 post-septal part of the organs. The funnels of the sperm-ducts are longer than in 

 any other Enchytraeus ; the proportion of length to breadth is about la : i. 



(7) Enchytraeus argenteus, Miohaelsen. 

 B. argenteus, Michaelsen, ibid. p. 15. 



Definition. Length, 5 mm. ; number of segments, 30 ; setae, a-3 jier bundle. Brain convex 



heUnd. Anteseptal part of nephridia of equal diameter with postseptal part, containing 



also a coiled lumen, duct comes of at right angles, and is long and distinct. Hob. — 



Germany {Elbe shore). 



This species appears to be the smallest of the Enchytraeidae. The name of the 



species was given to it on account of its silver colour, due to the dark pigmentation 



of the perivisceral corpuscles. 



(8) Enchytraeus hyalinus (Eisen). 



Neoenehytraeus hyalinus, Eisen, Ofv. Svensk. Akad., 1878, No. 3, p. 76. 

 B. hyalinus, Vejdovsky, Syst. u. Morph., 1884, p. 41. 

 E. (Weoenchytraeus) hyalinus, VaillaN'O^ Annel^s, p. 264. 



Definition. Length, 8 mm. ; number of segments 43 ; setae, 3 per bundle. Brain convex 



behind. Anteseptal part of nephridium long, with nearly straight duct. Spermathecae with 



a dilatation upon the d^ict, at opening of which are a few glands. Hob. — Nova 



Zemhla. 



Michaelsen (5, p. 40) distinguishes this species from E. adriaticus by the 



presence in the latter of numerous small pear-shaped glands ; I do not think that 



this difference will hold; Eisen figures (13, PI. x, fig. 201) quite similar glands in 



E. hyalinus. I do not perfectly understand the shape of the spermathecae from 



Eisen's figures ; he describes the spermatheca as consisting ' of two distinct parts, the 



lower one is funnel-shaped and wrinkled, and furnished at the base with small glands,' 



&c. I suppose that merely a dilatation of the duct is meant such as occurs in the 



species. 



