Article V. — A Preliminary Account of two New Oli- 

 gochceta from Illinois. By Frank Smith. 



Several species of Oligochseta were collected by the 

 writer during the past summer at the Biological Station 

 upon the Illinois River, at Havana, founded early in the 

 present year by the University of Illinois, with Prof. 

 S. A. Forbes as Director. Since it will be several months 

 before a full report on the Oligochaeta can be prepared, 

 it seems best to publish this preliminary account of the 

 larger forms collected. 



In the vicinity of the Station, the Illinois River flows 

 for the greater part of its course between low banks, 

 which are overflowed during the higher stages of water 

 that usually occur in the spring or early summer months. 

 They are covered with the usual bottom-land forests and 

 other vegetation of the region. In those portions of the 

 banks that are above water during the greater part of the 

 year, were found many earthworms of a species closelj" 

 allied to Diplocardia communis Garman. which was de- 

 scribed from Illinois in 1888* and is abundant in the 

 soil of the prairies of the State. Reproductive activity 

 was greatest throughout the month of May, when 



cocoons were abundant in their burrows. 

 t " 



Diplocardia ripaHa no v. sp. 



This earthworm is quite similar to D. communis in 

 general form, in relative length of somites in different 

 parts of the body, and in the plication and encircling 

 lines of the somites. The number of somites is similar, 

 the average of ten specimens being 150, the minimum 

 and maximum numbers respectively 136 and 157. 



The ordinary length of well-extended specimens is 22 

 to 25 cm., with a diameter of about .3 cm. 



*"0n the Anatomy and Histology of a New Earthworm (Diplocardia com- 

 munis, gen. et sp. nov.)." (Bull. 111. State Lab. Nat. Hist.. Vol. III.. Art. IV.. p. 47.) 



