266 CALIFORNIA ACADEMY OF SCIENCES. 



little varying in shape or size in sexually mature worms. 

 The lower part of the spermatheca is muscular, but there 

 are no glands at the base. The spermatheca fills the 

 whole width of the somite. 



Testes are found in two pairs, one in somite x and one 

 in xi, of the same shape and size as those in O. Beddardi 

 and other species. 



Sperm-sacs are found in somites ix, x, xi and xii, of the 

 same general form as those of O. Beddardi. The sperm- 

 sacs in somite ix are globular and lobed, but not as much 

 so as those in somite xii, which are deeply lobed, and 

 closely cover the anterior end of the sacculated intestine 

 like a collar. The sperm-sacs in O. Beddardi., agricola 

 and guatemalcs are all very similar. They do not enclose 

 nor even cover the testes, and the anterior and posterior 

 sperm-sacs are not connected with the middle ones. These 

 latter are unusually large in this species, occupying the 

 whole space in somites x and xi between the body-wall 

 and the other organs. They are larger than in any other 

 species of Ocnerodrilus. 



The ciliated rosettes and sperm ducts resemble those of 

 O. Rosce and contractus, but the prostate glands are much 

 longer, extending from somite xvii to xxviii, as in O. oc- 

 cidentalis, to which species, however, the present worm 

 shows no other afiinity. The sperm duct is enlarged, or 

 rather is surrounded by a muscular swelling close to the 

 male pore. The enlargement is about one-third as long 

 as the muscular part of the prostate. 



The muscular part of the prostate is very long, cover- 

 ing approximately two somites or more, while the gland- 

 ular part of the prostate extends through nine somites. 

 In the other species with similar structure of the male 

 organs, the prostate is much shorter. Thus in O. Hen- 

 driei and contractus, the glandular part of the prostate 



