no CALIFORNIA ACADEMY OF SCIENCES. [Proc 30 Ser. 



A perusal of the key shows that these subgenera are not 

 all of the same value. Omerodrilus (sens, str.) differs 

 from all others in its peculiar sperm-sacs and in the absence 

 of spermathecse. Enianodrilus and Ilyogenia, on the con- 

 trary, are more closely related. Nematogenia and Haplo- 

 drihts are quite distinct and had best be considered as 

 distinct genera. Nematogenia is especially remarkable on 

 account of its nematocytes or thread-cells, structures found 

 in no other oligochseta. 



Ocnerodrilus Eisen. 



Definition.— SmaW terrestrial or aquatic worms. Set^ eight, paired. 

 Clitellum includes the male pore in XVII. Pharyngeal and septal glands. A 

 pair of intestinal diverticles in IX. With or without spermathecag. One or 

 two pairs of testes. Ovaries in XIII. With or without racemose sperm-sacs. 

 With or without prostates, which, when present, open with the sperm-ducts, 

 or, when more than one pair, in the somite immediately behind. Prostate 

 contains only one layer of cells. No penial setae. Two pairs of hearts. Lat- 

 eral blood-vessels pass through the intestinal diverticles. Meganephridia 

 paired, present also in the anterior somites, generally with ccelomic cell- 

 mantle, sparsely traversed by blood-vessels. 



Key to the Subgenera and Species of Ocnerodrihts. 



Ocnerodrilus, Leiodrilus, Pygmcsodrilus, Ilyogenia, Enicmodrilus, Nemat- 

 ogenia and Haplodrilus. 



I. Prostates present. Two pairs of testes. No racemose sperm-sacs. 



Small, simple sperm-sacs capping the testes. No spermathec^. 



Ocnerodrilus Eisen, (sens, str.) 



1. occidentalis Eisen. 



2. ' occidentalis var. sinensis var. nov. 



3. occidentalis var. arizonce var. nov. 



II. Prostates present. Two pairs of testes. Racemose sperm-sacs. No 



sperm-sacs capping the testes. Spermathecae in IX, without 

 diverticles. 



Enicmodrilus, subgen. nov. 



4. Sperm-ducts with a thick muscular investment near the pore. 



Spermathecae large and globular. Prostates of medium size. 



agricola Eisen. 



5. Sperm-ducts with a thick muscular investment near the pore. 



Spermathecae long, cylindrical. Prostates thin, below medium 

 size. Sperm-sacs in IX very diminutive Roscb Eisen. 



