134 



swollen region merging gradually into the duct-like portion which 

 extends obliquely across the coelom to a point dorsad to the digestive 

 tract, where it bends caudad. It meets and unites with the sperma- 

 theca of the opposite side in the posterior part of V, to fonn the large 

 common duct which communicates with the digestive tract. 



Hexlea urbaxexsis n. sp. 



(PI. XII. Figs. 57-59) 



Definition. — Length, 2-^ mm. Diameter, 0.57 mm. Color, whitish 

 yellow. Prostomium blunt and rounded. Head pore at o I. Dorsal 

 pores absent. Setae of unequal length, the inner ones slightly shorter 

 and finer; slightly bent: 6-8 (usually 8) in ventral bundles; 4-6 in 

 lateral bundles. Clitellimi on K XI— XIII. L}Tnphocytes elliptical, 

 large. Brain about as wide as long; anterior margin concave, poste- 

 rior margin emarginate; lateral margins divergent caudad. Peptone- 

 phridia present and well developed, connected with digestive tract in 

 V; dorsal and ventral strands in close contact with digestive tract, 

 both showing conspicuous thickenings at origin which extend freely 

 into ccelom, the dorsal strand giving rise to tubules in \1, and the 

 ventral to similar tubules in Yl and \'II. Two "taste organs" in 

 buccal cavity. (Esophagus passes rather abruptly into intestine in 

 \'III. Two lateral sac-like diverticula in \'III, the cavity of each 

 communicating with lumen of digestive tract by one lateral opening. 

 Dorsal vessel arises in IX. Xephridia with small anteseptal and large 

 well-developed postseptal part, the efferent duct arising from ventral 

 surface of latter near septum. Spermiducal funnel moderate, length 

 about two and one third times greater than diameter. Spermatheca 

 not strongly developed ; no distinct ampulla ; diameter greatest in 

 region of external opening, where it is surrounded by a rosette of 

 glands; communicates with lumen of digestive tract on dorsal side by 

 means of a short channel formed by the fusion of the two sperma- 

 thecas at their ental ends ; ectal opening laterad, ^ear RyV. 



Described from one sexually mature specimen. Type in the col- 

 lection of the writer. 



The specimen which is the basis of this description was found in 

 late March, 191 1, near Urbana, Illinois, in the rich soil of undisturbed 

 forest-land. The specimen is sexually mature, since it shows sperma- 

 tozoa in the spermatheca?, well-developed ^gg masses in the body 

 cavity, and developing spermatozoa in XI. 



