144 Illinois State Laboratory of Natural History. 



The male pores are situited opposite the anterior part 

 of somite XIX and upon the ventral crests of the ridges, 

 being immediately outside of the tubercula pubertatis, 

 as in S. tam.esis. 



The last point of difference to be mentioned is the most 

 remarkable and unexpected. S. taraesis belongs to Ben- 

 ham's family Rhinodrilidse, in which, according to him, 

 prostate glands are absent.* There is no mention of 

 any such glands in his paper upon Sparganophilus. yet 

 glands that I consider to be homologous with them are 

 present in the form under consideration. These glands 

 require a somewhat detailed description, since their 

 number and position, and even their occurrence, is rather 

 remarkable. Each gland is tubular and of two well- 

 marked divisions; the true glandular part and the duct. 

 The former is more or less convoluted in an irregular 

 manner, and if straightened out would vary from .5 mm. 

 to 1 mm. in length. Its diameter is fairly uniform, and 

 usually about .13 to .15 mm. In a cross section of the 

 gland the lumen is nearly circular and about .015 mm. 

 in diameter. It is surrounded by. an epithelial layer 

 .006 to .01 mm. thick, and outside of this is the layer 

 of glandular cells, which is about .05 to .06 mm. thick. 

 Many of the cells of this la^^er are club-shaped, and 

 extend from the epithelial layer to the exterior, while 

 others extend only part way through the layer. This 

 part of the gland is surrounded by a plexus of blood 

 vessels from which many minute branches penetrate the 

 gland. The duct has a nearly sti'aight course through 

 the body wall, being but little longer than the thickness 

 of that wall, or about ."62 mm., with a diameter of 

 about .06 mm. The inner two thirds has a lumen much 

 smaller than that of the gland and often nearly oblit- 

 erated-. It is surrounded by an epithelial layer as in the 

 glandular region, but this is surrounded by a layer of 

 circular muscular tissue about .02 mm. thick, which 

 replaces the glandular layer of that region. The outer 



*"An attempt to classify Earthworms." (Quart. Jour. Micr. Sci.. Vol. XXXI., 

 1891, p. 221.) 



