ENCHYTR^ID^ 75 



In the two genera mentioned the structure is not known, and these 

 genera are only placed in this subfamily on account of their similarity 

 in other respects to the better known genera. The variability of the 

 structure of the setae is best known in Bryodrilus and Henlca^ where 

 some species possess straight setae while in others they are curved. 

 The genus Henlea is particularly variable, containing species in which 

 the setae resemble all the three forms — Lumbricillide, Enchytraeide and 

 Fridericia, 



Genus Lumbricillus Oerst. 



Definition. — Setae sigmoid, arranged in fan-shaped fascicles. 

 Head-pore small, situated between prostomium and peristomium. 

 Brain generally deeply emarginated posteriorly. Ventral sexual glands 

 around the ventral ganglion generally present. Blood red or yellow. 

 Dorsal vessel rises posterior to clitellum. No cardiac gland. No 

 peptonephridia. Testes multi-lobed, each lobe capped by a small 

 sperm -sac. Sperm-ducts comparatively narrow. Penial bulb without 

 inner muscular strands, containing only numerous glands of various 

 kinds, some of which may open into the basal part of the sperm-duct. 

 No atrium and no glands outside of the penial bulb. Nephridia with 

 entire postseptal and with an anteseptal which consists merely of the 

 nephrostome. 



To the definition of this genus by Michaelsen I have added the 

 points concerning the testes and the nephridia. The fact that the 

 testes are capped by small sperm -sacs has, I believe, not been previ- 

 ously noted. The small anteseptal, consisting of only a nephrostome, 

 is probably characteristic of this genus, though it is also found in 

 some other genera. 



DETAILED DESCRIPTION. 



Nephridia. — The nephridia in Lu?nbricillus are quite distinct as 

 regards the anteseptal part. In all the species which I have investi- 

 gated, as wxll as in all which I have seen figured, the anteseptal part 

 consists of merely the nephrostome. The postseptal is divided into 

 two parts, the lobe and the duct. The lobe is generally, if not always, 

 broad and disc-like and the duct is short. The postseptal lobe is fre- 

 quently furnished with granules or with bladder-like elevations near 

 the anteseptal. In the majority of species of Marionina the anteseptal 

 is large, resembling the Fridericia and Henlea type, while the Lum- 

 bricillus type is also seen in Enchytrceus. Even the postseptal part 

 of the Eumbricillide nephridium is characterized by its flatness and by 

 its more or less circular outline. 



