Species of North American OUgochcsta. 405 



cause of its relations to the other parts of the sperm-duct 

 correspouds to the "prostate" of E. frigidus, has thick 

 walls with layers corresponding to those of the reservoir 

 and the connecting duct, the chief difference between the 

 walls being- that in the former the ephithelial layer is 

 much thicker than in the two latter. There is no layer 

 of elongated glandular cells like that of the prostate 

 of E. frigidiis. At a point just anterior to the 

 septum X I XI is an enlargement of the duct and an 

 expansion of the lumen to form a small chamber 

 {at.. Fig. 7), in which is a marked change in the lin- 

 ing epithelium, this layer becoming much thinner and 

 the cells more scattered. The terminal ])ortion of the 

 duct extends from the chamber above referred to, ven- 

 trad to the male pore. The structure of this portion of 

 the duct leads me to believe that this worm has an eversi- 

 ble penis. A mass of glandular cells {gl. cH., Fig. 7) is 

 closely associated with the s])erni-duct at its external 

 opening. It consists of an aggregation of elongated uni- 

 cellular glands opening to the exterior upon the surface of 

 the body at the male pore. They are much like glands 

 similarly situated in some of the Lumbricidae. The nerve 

 cord IS slightly displaced in the region of the male pore, 

 where it leaves the middle of the ventral floor and lies 

 on one side of the sperm-duct. There is but one sperm- 

 sac, and this extends as far back as XXI, lying partly 

 beneath and partly to one side of the alimentary tract. 

 The reservoir of the sperm-duct with its external sheath 

 of tissue is partially surrounded by the cavity of the 

 sperm-sac. In somites X-XVII the alimentary tract is 

 upon one side of the body, being displaced by the large 

 mass consisting of sperm-sac and sperm-duct. There is 

 one pair of ovaries, in XI. They are large, irregularly 

 bent, and project part way into XII. The oviducts are 

 two in number, short, and open to the exterior at XI | 

 XII (PI. XXXVI., Fig. 8). Two spermathecse are situ- 

 ated in TX. but instend of lieing pnired they are both 



