1 88 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



and 148 represent one of the anterior and one of the posterior 

 spermathecae from the same specimen. The figures were 

 drawn from three sections. There is a muscular duct not 

 perceived from the exterior, being hidden by the other 

 spermathecal tissue. 



Sperm-sacs. — There are two pairs of sperm-sacs, both 

 strongly racemose, resembling those of Diplocardia carolin- 

 iana. The pair in IX is preseptal, that in XII postseptal. 



Prostates. — (fig. 149.) The four prostates are very 

 compact and when dissected appear as square irregular 

 masses. One of the prostates possesses a thin distal end 

 doubled on the main body of the prostate. The muscular 

 duct is narrow, slender, and coiled. The prostates do not 

 project dorsally and are confined respectively to one and 

 two somites. The penial setse opening with the prostates 

 are not half as long as the muscular part of the prostate. 



The structure of the glandular part of the prostate is 

 interesting as it shows a reduction of the inner epithelium. 

 The lumen is very narrow, narrower than the lumen of the 

 muscular part. It is numerously and irregularly branched, 

 the glandular cells opening into the branches as well as into 

 the main lumen. The whole prostate forms a single system 

 of glands, the secretions of which all flow into the common 

 narrow lumen. This lumen is lined, not by the regular 

 columnar epithelial cells, but by a thin nucleated membrane, 

 with here and there a few very small, distinct cells. The 

 prostate is in reality racemose, appearing tubular exteriorly. 

 See also the description of D. Michaelseni. 



Nephridia. — The nephropores are in line with setge d. 

 In form the nephridia closely resemble those of A. Keyesi 

 which have been figured elsewhere (Eisen 18). The wind- 

 ings and the spur are more folded and twisted. There is no 

 ccelomic mantle. 



Vascular System. — So far as can be judged from longi- 

 tudinal sections the dorsal vessel is single. There is a 

 peculiarity in the intestinal blood-sinus of some of the sexual 



