24 PEOCEEDINGS OF THE NATION" AL, MUSEUM vol.75 



extensive and widely scattered and some is not available to the writer. 

 There is, therefore, a possibility that the species just described above 

 is not new. 



OCTOCHAETUS LUNATUS. new species 



Description of the type-specimen, external characteristics (Cat. No. 

 19255,U.S.N.M.).— Length, 94 mm. Diameter, 3-5 mm. Number 

 of segments, 167. Color: Very light grayish, except the clitellum, 

 which is reddish. 



The prostomium is prolobous. 



On segments v-xii there is a deep secondary furrow posterior to 

 the setae of the segment. On segments vii-xi there is a secondary 

 furrow anterior to the setae of the segment. On segments vii-ix there 

 is a slight tertiary furrow on the posterior third of the segment. Poste- 

 rior to the clitellum there are usually two secondary furrows per 

 segment, one anterior to and one posterior to the setae of the 

 segment. 



The first dorsal pore is in 12/13. 



The setae are eight to each segment and begin on ii. Posterior to 

 the clitellum cd is nearly twice ah and is less than he, aa and he are 

 about equal. Posteriorly he diminishes until it becomes distinctly 

 less than aa. The dorsal distance is greater than one half of the 

 circumference. 



The clitellum extends from 12/13 to 18/19 (6). It is ringshaped 

 and complete except on xvii and xviii where it is interrupted by the 

 male area in aa. Intersegmental furrows and dorsal pores are lacking. 

 Setae are present. 



The male pores are in xviii, just internal to a, in the seminal 

 grooves. 



The female pores are paired in aa on xiv, each pore at the center 

 of a minute transversely oval papilla, the two papillae contiguous at 

 the center. 



The spermathecal pores are paired in aa on viii and ix, in line with 

 the eight setae of the segment. They are about the same size and 

 as readily visible as the female pores. 



The only genital markings are the seminal grooves which extend 

 across xviii onto the anterior portion of xix and the posterior portion 

 of xvii. The grooves are crescent-shaped and just internal to a. 

 The body wall between the two grooves is whitish. 



Internal anatomy. — Septum 4/5 is present and thickened; 5/6, 6/7, 

 and 7/8 are absent; 8/9, 9/10, 10/11, and 11/12 are thickened and 

 very close together; 12/13 is very slightly thickened. Septa 10/11 

 and 11/12 are bound together by a connective tissue in such a way 

 as to close off a central portion of segment xi as a sort of testicular 

 chamber which must be opened before the contents can be seen. 



