REMARKABLE SPECIES OF ECHIUROIDS. 13 



shown in lîg. 14. The tubes finally terminate each with a large 

 ciliated fiiunel and may be called the funnel-stalk of unusual 

 length. Their wall shows the same histological structure as the 

 vas deferens of other Bonellian males, being made up of tliree 

 layers ; viz., 1) the peritoneal epithelium (fig. 14, ^jr.), 2) the 

 thin connective-tissue layer {c.t.l.) and 3) the endothelial layer 

 of the lumen (eut.). Both the peritoneal and endothelial layers 

 consist of flat cells, except at the outflaring distal end of the 

 funnel where the covering epithelium consists of cylindrical cells 

 thickly ciliated on the exposed surface. The transitions of the 

 flat peritoneum into this ciliated thickened epithelium takes place 

 abruptly. In fig. 15 is shown a cross-section through a funnel 

 right close to the internal opening. In it the non-ciliated 

 thickened epithelium of the lumen is seen at two opposite places 

 to pass directly into the outer ciliated epithelium and at other 

 places to be separated from the latter by the connective-tissue, 

 owing to the uneven configuration of the funnel mouth that had 

 probably been brought about by the action of the fixing reagent. 



Male Sexual Cells. — Small masses of spermatozoa are found 

 floating in abundance in the cœlomic fluid. Each mass, spherical 

 or ovoid in shape, consists of a central, comparative large sper- 

 matophore bearing numerous spermatozoa in the periphery. The 

 former can scarcely be stained and is commonly vacuolated (fig. 



14, S.171.). 



As to the origin of the sperm-masses, two irreconcilable 

 opinions had been advanced by previous authors. According to 

 one view, they are formed in the parenchyma of the body-wall, 

 i.e., in a. tissue which corresponds, as far at least as the position 

 goes, to what I have called the trabecular layer in the male of 



