152 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



4. Gizzard rudimentary. Nephridia commence in II. Race- 



mose sperm-sacs in XI and XII. Anterior setae not con- 

 verging; posterior converging. Sperm-ducts join pros- 

 tate before they enter the body-wall, half-way up the 

 muscular part. Nephropores without sphincter. 



Microscolex Carolines, sp. nov. 



I I . Two pairs of testes. Spermathecae present, with one diverticle each. 



5. No gizzard. No penial setae. Sperm-ducts join the pros- 



tates in the body-wall. 



Microscolex algeriensis Beddard (38). 



6. Gizzard rudimentary. Penial setae present. Sperm-ducts 



open on segment behind the prostates. 



Microscolex phosphoreus (Duges) Michaelsen (30). 



7. Gizzard rudimentary. Setae convergent. Penial setae smooth, 



with end knob. Sperm-ducts open into the prostates. 



Microscolex Horstii, sp. nov. 



III. Two pairs of testes. Spermathecae present, with two diverticles 



each. 



8. No gizzard. Distance a-b several times smaller than c-d. 



Microscolex Benharni (Eisen, 16). 



9. No gizzard. Distance a-b about equal to c-d. 



Microscolex Troyeri (Eisen, 16). 



10. Gizzard rudimentary, in V. Setae not converging. All 



nephropores in front of setae c. Prostates and sperm- 

 ducts open together in the same pore. 



Microscolex novce-zelandicB Beddard (25). 



11. Gizzard rudimentary, in V. Setae converging. Sperm-ducts 



open into the muscular prostate. Nephropores II-IV in 

 front of setae d Microscolex parvus, sp. nov. 



12. Gizzard rudimentary, in V. Setae converging. Nephro- 



pores II-IV in front of setae d. Prostates and sperm- 

 ducts open in separate pores. 



Microscolex Hempeli Smith (3). 



13. Gizzard in VIII. Sperm-sacs in XII. Prostomium com- 



plete Microscolex mofiticola Beddard (86). 



B. One pair of testes. 



Yagansia Michaelsen (30). 

 I. Spermatheca with one diverticle each. 



1. Gizzard in V. Prostomium incomplete. Setae paired; 



penial setae long. No dorsal pores. Spermathecae in IX. 

 Sperm-sacs in IX and XI. Prostates extend back many 

 somites Yagansia papulosa (Beddard, 87). 



2. Gizzard in VI. Prostomium incomplete. Setae paired. 



Penial setae long. Dorsal pores present. Spermathecae 

 in IX. Sperm-sacs in XI. 



Yagansia longiseta (Beddard, 87). 



3. Gizzard in VI. Prostomium complete. Setae paired; 



penial setae curved, without exterior sculpture. Sperm- 

 sacs in XI. 



Yagansia pallida Michaelsen (28). 



