32 



BULLETIN 69, UNITED STATES NATIONAL MUSEUM. 



Dorso-ventral fibers are fairly numerous throughout the segment, but 

 transverse fibers are not present. 



Excretory system (figs. 23, 24, d. ex.^ v. ex.). — In sexually active 

 segments the ventral excretory canals measure from 25 to 50/x in 



ut. 



d .ex . 



G.p. 



locju.. 

 Fig. 24. — Rhabdometra similis : Sexually mature segment^ becoming gravid, 

 transverse section. c. p., cirrcs pouch. d. ex., dorsal excretory vessel. i. 11., 

 Nerve cord, ut.. Uterus, v. ex.. Ventral excretory vessel. 



diameter, the dorsal canals 8 to lO/x. The latter are located dorsal of 

 the ventral canals in about the same vertical longitudinal plane. In 

 the posterior portion of each segment the ventral canals are connected 

 by a transverse canal. 



v.def 



vag 



Fig. 25. — Rhabdometra similis : Section through cirrus pouch a\d vagina, dr.. 

 Cirrus, c. p.. Cirrus pouch, vag.. Vagina. (■. def.j, Vas deferens. 



The vagina and vas deferens pass between the excretory canals and 

 dorsal of the lateral nerve. 



Male reproductive organs. — The testicles (fig. 23, t.), numbering 16 

 to 20, are located in the posterior third of the segment, are oval in 



