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



The subgenus is named for Professor A. Van der Naillen 

 of San Francisco. This very interesting form differs from 

 all other members of the genus in the position of the sperm- 

 iducal pores, in XVIII, showing the extent of the variation 

 of these pores in the same genus. It stands at one end of 

 the series, while Dirplocardia Keyesi stands at the other, 

 giving an extreme variation of four somites in which are 

 located the male pores. D. Koehelei differs from all other 

 species of Di^locardia in not possessing racemose, pre- 

 septal sperm-sacs in IX, a character which seems to join 

 it more closely to the Benhamia group, and perhaps to 

 Trtgaster. 



Detailed Description. 



Somites. — Somite I is dorsally as wide as somite III, veh- 

 trally as wide as somite II. Somites II and III are narrower 

 than those following, which slightly increase in size pos- 

 teriorly, at least as far as X or XII. 



Clitellum. — The clitellum is not developed in any of the 

 specimens, and it is possible that it is altogether absent. The 

 large papillae surrounding the prostate pores may serve as a 

 substitute for a clitellum. These papillae show the same 

 structure as that described in the tubercula pubertatis of Pon- 

 toscolex, except that the glandular cells are much larger and 

 extend not only into the muscular layers, but far beyond 

 them into the coelomic cavity of the body. These glandular 

 masses form a continuous stratum on the ventral side of 

 somites XVII, XVIII and XIX, but are especially developed 

 back of the prostate pores, where they extend to the centre 

 of the coelomic cavity, touching the sides of the intestine. 

 These glands do not open into any special pore, as is the 

 case in some other species where, for instance, they open 

 into the papillae of the spermathecae. They open on the 

 surface in exactly the same manner as the large glandular 

 cells of the clitellum. The glands do not occur singly, but 

 in bunches. I am inclined to regard them as modified 

 clitellar cells. 



