178 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.52. 



a quite homogeneous group. In addition to the characters mentioned 

 in the definition, they all have closely paired setae, and no traces of 

 spermathecae have been found in them. Since //. zeteM has the cli- 

 tellum extending posteriad as far as 37, the anterior position can no 

 longer be considered as characteristic of the subgenus. In view of 

 the tendency of H. tenuis to develop spermathecae, it might simplify 

 matters to place it in a subgenus, as Dendrolaena, which normally 

 has spermathecae and leave II. oculatus in the subgenus EopMla, and 

 thus have a much more homogeneous group in Bimastus. Michaelsen 

 is certainly justified in considering the border line between Bimastus, 

 Dendrohaena, and Eophila as one of the most puzzling problems in 

 the system of Lumbricidae, 



H. tenuis is most commonly found in and under fallen timber and 

 in leaf mold and has been reported as H. constrictus, from various 

 places in Europe, Asia, and South America. In North America, it 

 has been listed from Mexico, New York, Illinois, California, Canada, 

 Vancouver, and Alaska. 



New localities: Maine, Ohio, Indiana, Michigan, Colorado, Wash- 

 ington, and Bering Island. 



Genus OCTOLASIUM Orley, emended by Rosa. 



Prostomium, usually epilobic, occasionally tanylobic. Sperm 

 sacs, four pairs in 9-12. Spermaries and spermiducal fminels, en- 

 closed in paired sperm vesicles or in narrow chambers. Setae, usually 

 widely paired or separate. Orley (1885 : 13). Rosa (1893 : 424). 



OCTOLASIUM LACTEUM (Orley). 



Lumbricus terrestris var. lacteus Orley, 1881: 584. 

 Octolasion lacteum Orley, 1885: 21. 

 Octolasium lacteum Michaelsen, 1900a: 506. 

 Allolobophora profuga Rosa, 1884: 47. 



Length, very variable, 5-16 cm. Somites, 100-165. Color of few 

 anterior somites, pale pinkish; posterior end is pale; remainder of 

 body except clitellum is blue-gray when the intestine contains the 

 usual amount of earthy matter. Ptostomium, usually epilobic i-§ ; 

 occasionally tanylobic. Setae anterior to the clitellum, definitely 

 paired, and ah less than he; posterior to the chteUum, the setae 

 are scarcely paired, and ah is equal to or greater than he; he is 

 greater than ed, in general. Clitellum on 30-35. Tubercula puber- 

 tatis on 31-34. First dorsal pore on 8/9, 9/10, or 10/11. Spermi- 

 ducal pores on 15; nearer to c than to h. Oviducal pores on 14, 

 slightly dorsad of h. Spermathecal pores on 9/10 and 10/11, in line 

 with c or d. Septa 6/7-8/9, slightly thickened; and 9/10-13/14, still 

 less thickened. The calciferous gland commimicates at its anterior 

 end with the esophagus in 10 and has about 45 longitudinal parti- 

 tions. Spermaries and spermiducal fimnels in 10 and 11, included 



