28(5 ARTHUR E. SHIl'LEY. 



specimen a median nerve seemed to leave the ganglion between 

 the anterior two nerves. It is probable that this nerve 

 divides into two branches. 



Reproductive System. — The external opening of the 

 vas deferens and of the uterus lie side by side, close to one 

 another, at the posterior end of the body. 



The male rejiroductive organs consist of paired branching 

 testes. Each halt' presents some ten or twelve twigs lying on 

 either side of the anterior end of the digestive sac, and ex- 

 tending in front of the mouth (fig. 5). These twigs fill up most 

 of the sides of the body, from in front of the mouth to the region 

 of the yolk-glands. The several branches of each half of the 

 testis unite and open into a pair of tubes, which may be termed 

 the vasa effereutia. These soon fall into one another, and 

 form a long median and anteriorly much-coiled tube. This 

 vas deferens makes a well-marked loop forward to the left of 

 the mouth (fig. 4). In its hindermost part, howevei', the 

 tube is straight, and is provided with thick muscular walls 

 lined with a cuticle. 



Russo describes a complicated penis. I have not been able 

 to follow all his details, but there is undoubtedly a protrusible 

 iutromittent organ present. 



The histology of the male reproductive organs presents little 

 worthy of notice. The branches of the testis were outlined 

 by a very thin basement membrane, but beyond this they 

 presented no special investiture. Their contents were cells 

 of some size with large nuclei and conspicuous chromatin. 

 Near the end next the ducts, bundles of tailed spermatozoa 

 are to be seen. The vas deferens is a long and much-coiled 

 duct, so that, as a rule, portions of it are seen several times in 

 any one section. It has a smooth internal wall or cuticle, 

 and apparently a thin muscular lining; at the posterior end 

 the wall of the tube is very much thickened by a stout 

 muscular sheath, and this portion is protrusible, and indeed in 

 one specimen is protruded as a penis. 



The ovary, like the testis, is doul)le and branched ; each half 

 is compared by Fran9ois to a hand with the fingers extended. 



