44 E. NOMURA: 



b. The funnel is peculiarly modified to form a flame-like 

 structure. 



4. Vascular system : 



a. The absence of the commissural hearts and of the 



vessels which directly connect the dorsal and ventral 

 vessels. 



b. The absence of distinct supra- and sub -intestinal vessels. 



c. The presence of unicellular valves in the dorsal vessel. 



5. Genital system : 



a. The presence of a pair of testes in segment X. 



b. The presence of a pair of ovaries in segment XI. 



c. The spermathecal pores may be paired or united into 



one and lie in segment X. 



d. The male pores also may be paired or unpaired and 



lie in segment XI. 



e. The absence of spermotophores. 



f. A short vas deferens or atrial duct-portion opens into 



a non-ciliated, elongate chamber. 

 In conclusion, the more prominent characters of Rhizodrilus 

 Smith as compared with Monopylephorus Levinsen may be recapi- 

 tulated as follows : 



1. The presence of a pair of elongated tubular glands in 

 segment IX, opening in close relation with the ventral modified setae. 



2. The presence of peculiarly modified setœ on the ventral 

 side of segment XL 



3. The presence of commissural hearts which do not give off 

 branches to the body wall. 



4. The absence of a flame -like structure in the nephridial 

 funnel. 



5. The absence of unicellular valves in the dorsal vessel. 

 These characters, especially 3, 4, 5, appear to me to be of 



