170 



Enchytr^us gillettensis n. sp. 

 (PI. XII, Figs. 52-56) 



Definition. — Length, 2.5-4.5 mm. Diameter, 0.144-0. 188 mm. 

 Somites, 25-27. Color, whitish. Prostomium blunt and rounded. 

 Lymphocytes few in number, ovoid, nucleated. Setae straight, those 

 of a bundle of equal size; number per bundle, 2-3, rarely 4 or 5. 

 Clitellum on XII-XIIL Brain about twice as long as broad ; anterior 

 margin concave; posterior margin almost straight; lateral margins 

 converging cephalad. Peptonephridia present, arising from dorsal 

 surface of pharynx in III as two separate organs ; slightly branched ; 

 usually terminating in a large mass. Dorsal vessel arises in XIV. 

 Anteseptal part of nephridia small and inconspicuous, comprising little 

 more than the nephrostome; postseptal part large; short efferent duct 

 arises from posterior end of postseptal part. Length of spermiducal 

 funnel 3 to 4 times the greatest diameter; collar distinct; distinct bend 

 in middle of funnel. Duct of spermatheca about four times the length 

 of ampulla and completely covered with small glands ; ampulla spheric- 

 al, thin-walled, destitute of diverticula, and connected with digestive 

 tract. 



Described from fifteen specimens, all of which are sexually mature. 

 Type and paratypes in the collection of the writer. Paratypes. also in 

 the collection of Professor Frank Smith. 



The specimens which form the basis of this description were col- 

 lected by Dr. George R. LaRue at Gillette Grove, Iowa, in August, 

 1910. They were found in damp black soil, under the drip of a build- 

 ing. 



Affinities. — X^othing definite can be accomplished in attempting to 

 establish the relationships of this species owing to the incomplete and 

 ambiguous descriptions of some of the European species. All that can 

 be done at present is to call attention to the apparent similarity which 

 exists between this form and some of the other species as judged by 

 those characters which are described in sufficient detail to be used in 

 diagnosis, keeping in mind meanwhile the possibility that future in- 

 vestigation may show that they are not at all closely related. This 

 species approaches B. argenteus Mchlsn. closely in some respects, but 

 shows differences in the characters of the nephridia, the spermiducal 

 funnel, and the spermathecse. In other particulars it resembles B. 

 sabulosits Southern, but distinct differences exist in size, number of 

 somites, the brain, and one or two other organs. It also resembles 

 B. indicus Steph. but differences exist in the peptonephridia and the 

 spermathecse. Of the American species it most nearly approaches B. 



