36 



E. NOMURA : 



U 



cLl i.u 



sp 



not fully developed the saccular portion is comparatively elongated 

 and reaches from the anterior septum to about the middle of the 

 segment, and suddenly bending ventro- internally at its anterior end 

 opens into the common duct portion, which in turn opens to the 

 exterior at the anterior one-fifth or one-sixth of the segment length, 

 on the ventral median line of the body. 



The inner cavity 

 of the spermatheca is 

 spacious. The sperma- 

 tozoa arc diffusely 

 scattered and never 

 form spermatophores. 

 The wall of the 

 duct portion consist 

 distinctly of five layers, 

 which are direct con- 

 tinuations of those of 

 the body wall. The 

 inner surface is covered 

 by a, thin cuticle ; the next cellular layer is irregularly folded and 

 consists of exceedingly slender cells with a dense cytoplasm and 

 an elongated nucleus at the base ; the circular muscle layer is pretty 

 well developed but the longitudinal very feebly ; the outer peri- 

 toneum is similar to that of the body wall. In the saccular por- 

 tion the two outer layers are very thin, while the circular muscle 

 and the cellular layers remain well developed, and the cuticle is 

 totally imperceptible although undoubtedly present. 



So far as my observations go, as the ova become fully ripe 

 the inner cavity seems to become gradually reduced and the wall 

 becomes highly muscular. 



5). Ovaries. One pair of ovaries are attached to the posterior 



i 



d.p 



Fig. 30. 

 Cross section through segment X of a comparatively 

 young specimen, near the spermathecal pore. x 150. 

 Coelomic corpuscles are not shown. 1.1 — lateral line, 

 chl — chloragogues, i.n — intestinal vascular network, d.v 

 — dorsal vessel, te — testes, sp — saccular portion of sperm- 

 atheca, dp — duct portion of spermatheca. 



