268 CALIFORNIA ACADEMY OF SCIENCES. 



Ocnerodrihis occidcutalis than in any other species so far 

 known. Instead of two pairs of testes there is only one 

 pair. This one situated in somite x, attached to the 

 anterior septum. It is of the same general structure as 

 the posterior testes in O. Beddardi, small, thin and heart 

 shaped. Instead of a pair of testes in somite xi, as might 

 be expected from analogy with other species, we find 

 in this somite a pair of small sperm-sacs, which might 

 be mistaken for testes, and were so at first consid- 

 ered bv myself. They are attached to the anterior 

 septum, varying in size, but always only slightly larger 

 than the testes, and never attaining to the size of the 

 sperm-sacs of the other species. This sperm-sac, which 

 is situated in line with the testes in the somite in front, is 

 rounded, almost globular, with a more or less irregular 

 surface, like a more or less inflated or collapsing balloon. 

 It is furnished with a lower duct, which consists of a 

 muscular and glandular layer of cells which in the duct 

 are strongly ciliated. This duct reaches only to the 

 septum in somite xi, and then connects from there with 

 the anterior testes. I suspected first that this muscular 

 duct connected with the exterior through the body-wall, 

 in which case the sperm-sac would have served also as a 

 spermatheca, this organ being absent in this species, but 

 I could not find any connection between it and the body- 

 wall. 



The lobed sperm-sacs which in other species are found 

 in somites ix and xii, are not found in this species, nor is 

 there a pair of sperm-sacs in x, as in all other species. 



T\\^ prostate gland is very long, several times bent on 

 itself, and extending from somite xvii to xxvi, when fully 

 developed. The ciliated rosettes are in somites x and 

 xi, behind the testes and sperm-sacs. The sperm ducts 

 pass posteriorly and open with the prostate in somite vii. 



