340 OLIGOCHAETA 



the doubtful species E. ajfi.nis. This resemblance to Pachydnlus 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 12:1. 



(7) Enchytraeus argenteus, MICHAELSEN. 

 E. argenteus, MICHAELSEN, ibid. p. 15. 



Definition. Length, 5 nm. ; number of segments, 30 ,- setae, 23 per bundle. Brain convex 

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

 also a coiled lumen, duct comes off at right angles, and is long and distinct. Hal. 

 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). 



Neoenchytraeus hyalinus, EISEN, Ofv. Svensk. Akad., 1878, No. 3, p. 76. 

 E. hyalinus, VEJDOVSKY, Syst. u. Morph., 1884, p. 41. 

 E. (Neoenchytraeus) hyalinus, VAILLANT, Annele"s, p. 264. 



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

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

 a dilatation upon the duct, at opening of which are a few glands. Hab. Nora 

 Zembla. 



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. 



