Illinois Oligochceta. 443 



Rhizodrilus lacteus n. g. et n. sp. Havana; abundant 

 locally. 



Embolocephahts multisctosus n. sp. Havana; abundant 

 locally. 



Naidomorpha. 1 



Nais lacustris Linnaeus. Urbana and Havana ; abundant. 

 Nais elinguis 0. F.Miiller. Urbana and Havana ; abundant. 

 Nais lurid a Timm. Havana; frequent. 

 Nais serpentina 0. F. Miiller. Havana; frequent. 

 Dero limosa Leydig. Havana ; abundant. 

 Dero obtusa D'Udekem. Havana ; abundant. 

 Dero vaga Leydig. Havana ; abundant. 

 Dero /areata Oken. Havana; frequent. 

 Pristina leidyi Smith. Havana ; abundant. 

 Pristina flagellum Leydig- Havana ; one specimen. 

 Chcetog aster limncei v. Baer. Havana ; abundant. 

 Chcetogaster diaphanus Gruithuisen. Urbana and Havana ; 

 abundant. 



Chcetogaster diastrophus Gruithuisen. Havana; abundant. 



JEolosomatidee. 



sEolosoma hemprichii Ehrenberg. Urbana and Havana; 

 frequent. 



JEolosoma tenebrarum Vejdovsky. Havana; abundant. 

 Mblosoma sp. 2 Havana; abundant. 



DESCRIPTIONS OF TUBIFICID.E. 



# 



As the first two species of Tubificidce in our list are well- 

 known European forms which have been described at length 

 by previous writers, a brief recapitulation of some of their 

 more important characters will suffice in this connection. 



1 But little attention has been given to the Naidomorpha of Urbana. 



2 A species with colorless integumental globules, not yet described. 



