162 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.52. 



entire gland poorly developed as compared with those of many 

 lumbricid species. Sperm sacs in 9-12. Spermathecae on dorsal 

 side, chiefly in septa 9/10 and 10/11. This position of the sper- 

 mathecal pores is the more usual one and is stated by Cognetti (1905) 

 to be the normal one in European specimens. It differs from the 

 statements of Rosa (1893), Michaelsen (1900a), and of Smith (1915). 



H. tetraedrus f . typica finds favorable conditions in the water-soaked 

 banks of streams, lakes, and ponds. It is distributed generally 

 throughout Europe and m many parts of the world where Europeans 

 have settled. In the United States it has been reported from Penn- 

 sylvania and California. 



New localities: Ohio, Michigan, Indiana, Illinois, Colorado, and 

 Washington (Puget Sound region). 



HELODRILUS TETRAEDRUS forma HERCYNIA (Michaelsen). 



Allurus hercynius Michaelsen, 1890: 7. 



Eiseniella tetraedra hercynia Michaelsen, 1900rt; 473. 



EelodriliLS {Eiseniella) tetraedrus f. hercynia Michaelsen, 1910: 11. 



Similar to f. typica except that the spermiducal pores are on 15 

 instead of 13. 



The habitat is the same as that of f. typica, but the reported dis- 

 tribution is less extensive, being limited to parts of Europe, and in 

 the United States to California. 



New locality: It is abundant at Urbana, Illinois, in association 

 with f . typica. 



HELODRILUS TETRAEDRUS forma NEAPOLITANA (Orley). 



AUurtLS neapolitanus Orley, 1885: 12. 



Eiseniella tetraedra neapolitana Michaelsen, 1900a; 473. 



Very similar to f . typica in most respects, but differs in the following : 

 Length (maximum), 8 cm.; somites (maximum), 150; clitellum on 

 20 or 21-24 or 25; tubercula pubertatis on 21-^24 or 24. The 

 spermiducal pores are on 13 as in the typical form. 



Forma neapolitana is known from Italy and from California. 



HELODRILUS TETRAEDRUS forma NINNII (Rosa). 



Allolobophora ninnii Rosa, 1886: 680. 

 AUurus ninnii Michaelsen, 1890: 10. 

 Eiseniella tetraedra ninnii Michaelsen, 1900a.- 473. 



Similar to f. typica, but differs in the following respects: Somites, 

 120-130; clitellum on 20 or 21-24 or 25; tubercula pubertatis on 21 or 

 22-24; spermiducal pores on 15. 



The chief difference between this form and f . neapolitana is in the 

 position of the spermiducal pores. 



Forma ninnii has been reported from Italy, Western Asia, and 

 California. 



