ZooL.-VoL. II.] EISEN--OLIGOCH.¥.-TA. 153 



4. Gizzard in VI. Setae paired; penial setse with crenate 



ridges. Sperm-sacs in XI. 



Yagansia spatulifer Michaelsen (13). 



5. Gizzard in VI. Prostomium complete. Setse paired; 



penial setae with spinelets. Sperm-sacs in IX and XI. 

 Spermathecal diverticle forked. 



Yagansia grisea (Beddard, 87). 



6. Gizzards in VI and VII. Prostomium complete. Setse 



separated; penial setae smooth. Dorsal pores present. 

 Sperm-sacs in IX and XI. Sperm-ducts open separately 

 from the prostates. 



Yagansia diversicolor (Beddard, 87). 



7. Gizzards in VI and VII. Prostomium complete. Setae 



paired; penial setae with transverse ridges, flattened and 



wider at apex. Dorsal pores present. Sperm-sacs in XI. 



Yagansia corralensis (Beddard, 87). 



8. Gizzard in VII. Prostomium complete. Setae separated; 



penial setae smooth. No dorsal pores. Sperm-sacs in 

 XI. 



Yagansia robusta (Beddard, 87). 



9. Gizzard in VIII. Prostomium complete. Setae separated; 



penial setae smooth. No dorsal pores. Sperm-sacs in 

 XI and XII. 



Yagansia gracilis (Beddard, 87). 

 II. Spermathecae with two diverticles each. 



10. Gizzards rudimentary. Sperm-ducts open behind the 



prostates in a groove. Penial setae with spinelets. 



Yagansia Michaelseni (Beddard, 87). 

 C. Two pairs of testes; four pairs of spermathecae, in VI-IX. 

 Rhododrilus Beddard. 



Rhododrilus niinutus Beddard (37). 



Microscolex Rosa. 

 Microscolex elegans (Risen), 



Deltania elegans Eisen, Mem. Cal. Acad. Sci., Vol. II, No. 5, 1896. 



The following additional characteristics not mentioned in 

 the former description are of considerable interest: — 



Gizzard. — There is a small rudimentary gizzard in somite V. The trans- 

 verse muscular layer is increased some three or four times, but still is not 

 sufficiently thick to form a perfect gizzard. The intestine widens but little in 

 this somite and cannot be seen well except in sections. 



Spermathecce. — There are no real spermathecae and the peculiar sacs filled 

 with spermatozoa found in the specimens first described are of doubtful char- 

 acter; they do not open exteriorly. Similar structures have not been found 

 in any specimens dissected or sectioned recently. 



