296 Jlli/nois State Laboratory of Natural Histoinj. 



kindness I have been permitted to work during the past 

 summer in the laboratory and library of the Museum 

 of Comparative Zoology, and especially to Prof. S. A. 

 Forbes, of the University of Illinois, whose continued 

 encouragement and assistance have enabled me to carry 

 on my study of this interesting group of animals. 

 Champaign, Dec. 12, 1895. 



LIST OF PAPERS CITED. 



1. Beddard, F. E. — A Monograph of the Order Oli- 



gochceta. 1895. 709 pp., 5 plates. 



2. Benham, W. B.— a New English Genus of Aquat- 



ic Oligochaeta (Spaiganophilus), belonging to 

 the Family Rhinodrilidae. 1893. Quart. Journ. 

 Micr. Soc, Vol. XXXIV., pp. 155-179, PI. XIX. 

 and XX. 



3. EiSEN, G. — On the Oligochaeta collected during the 



Swedish Expeditions to the Arctic Regions in the 

 years 1870, 1875, and 1876. Kongl. Sv. Yet.- 

 Akad. Handl., Bd. 15, No. 7. 1879. 



4. Hesse, R. — Die Geschlechtsorgane von Lumbricu- 



lus variegatus Grube. 1894. Zeit. f. wiss. Zool., 

 Bd. LVIIL, pp. 355-363, Taf. XXII. 



5. Leidy, J.— Descriptions of some American An- 



nelida abranchia. 1850. Journ. Acad. Nat. 

 Sci. Phil., Vol. II., 2d ser., pp. 43-50, PI. II. 



6. MiCHAELSEN, W. — Untersuchuugeu liber Enchytraeus 



Mobii Mich, und andere Enchytraeiden. Kiel, 



1886. 50 pp., 3 Tafeln. 

 7. Synopsis der Enchytraeiden. 1889. Ab- 



handl. d. Naturw. Ver. Hamb., Bd. XL, Heft I., 



60 pp., 1 plate. 

 8. Die Rcgenwurm-Fauna von Florida und 



Georgia. 1894. Zool. Jahrb.. Abth. f. Syst. Bd. 



VIII., 2 Heft, pp. 177-194. 



