25] PROTEOCEPHALIDAE — LA RUE 25 



The cirrus-pouch, cirrus, ductus ejaculatorius, vas deferens, vasa 

 efferentia, and testes comprise the male reproductive system. 



The cirrus-pouch is a more or less cylindrical or ovoidal muscular 

 bag which contains the cirrus and ductus ejaculatorius. At its outer end 

 it is attached to the wall of the genital atrium by means of some of its 

 muscle fibers. At the other end strong muscle fibers attach it to the 

 inner dorsal surface of the muscle sheath. Some muscles are also con- 

 tinued into the cirrus itself. The form and size of the cirrus-pouch is 

 reasonably constant for each species if proglottids of the same degree of 

 development be considered. Hence the length of cirrus-pouch relative 

 to the breadth of the proglottid is useful as a diagnostic character. In 

 some instances the cirrus-pouch is somewhat constricted about the mid- 

 dle. This condition seems to be correlated with the act of protrusion, as 

 the writer points out under a later caption. The greatest diameter is 

 usually found at the inner end of the pouch. 



The more or less muscular cirrus, a tube the two ends of which vary 

 somewhat in structure, passes through the length of the cirrus-pouch. 

 The outer portion of the tube is called the cirrus while the inner and 

 less muscular end is called the ductus ejaculatorius. Each part is char- 

 acterized by certain structures tho the one grades over into the other 

 almost imperceptibly. The cirrus possesses both circular and longitudi- 

 nal muscles. The circular muscles are most heavily developed near the 

 base or outer end of the cirrus while they are greatly reduced in the end 

 where it passes over into the ductus ejaculatorius. Longitudinal muscles 

 are weakly developed. At the outer end strands of muscle pass out from 

 the cirrus to the wall of the cirrus-pouch. There are very few if any 

 gland cells on its exterior. Its internal surface is lined by a continuation 

 of the cuticula of the atrium. Toward the inner end of the cirrus the 

 cuticula gradually disappears until at the inner end it is difficult to dis- 

 tinguish. The muscles also become weaker and the outer diameter of 

 the tube may consequently diminish in size tho in some species this 

 region may be inflated. With the change in the musculature and the 

 thinning of the cuticular lining prostate gland cells appear. These char- 

 acters mark the ductus ejaculatorius, namely, the thin wall, weak mus- 

 cles, little or no cuticula, and the presence of the prostate gland cells. 

 This region may be swollen into a voluminous tube for the retention of 

 spermatozoa and hence with the coils of vas deferens may serve as a 

 vesicula seminalis. There is no specialized vesicula. The cirrus itself 

 is usually quite straight and is only rarely thrown into coils. The ductus 

 ejaculatorius is frequently straight tho in a large proportion of the spe- 

 cies it is bent or coiled in one to several coils. 



