212 Memoirs of the Indian Museum. [Vol. VII, 



Perionyx alatus, sp. no v. 



Plate IX, figs. 14-16. 



Sitong Ridge, alt. ca. 4,700, ft. ; Darjiling Dist.,E. Himalayas. 22-28-X-1917. N. Annandale 

 and F. Gravely. Three specimens. 



External Characters : — Length 84 mm.; diameter 3 mm. Colour dusky purple 

 dorsally; pale, slightly brownish below. Segments 123. 



Prostomium epilobous |, tongue not closed behind. 



Dorsal pores begin from groove 4/5. 



The setal rings are closed dorsally and ventrally ; the setae are closer set ven- 

 trally. The following numbers were counted : — v/50, ix/55, xii/ca. 54, xix/50, and 

 in the middle of the body ca. 52. 



The clitellum extends from segment xiii as far as the anterior third of xvii 

 (=4!). It is slightly lighter in colour, and is the same diameter as the rest of the 

 body ; setae and intersegmental grooves are visible. 



The male field takes up the whole of the ventral surface of segment xviii (fig. 14). 

 Its rounded lateral borders occupy the ventro-lateral region of the segment, and its 

 anterior and posterior borders correspond with the limits of the segment. Its chief 

 feature is the presence of a pair of large transversely elongated papillae, conjoined 

 by a narrow neck in the middle line, their outer ends rather narrower, and their 

 margins crenulated. The conjoined papillae are surrounded by a deep groove or 

 moat. The male pores appear as transverse grooves in the broader, inner part of 

 the papillae ; the actual openings seem to be at about the middle of the grooves, 

 the distance between them being approximately one-fourth of the transverse extent of 

 the visible ventral surface, as seen looking down on it. The penial setae are seen as a 

 number of black dots in the grooves. 



The female aperture is represented by a mid- ventral small depression anteriorly 

 on segment xiv. 



The spermathecal pores are two pairs, in grooves 6/7 and 7/8, the same distance 

 apart as the male pores, about in line with the setal interval de. 



Internal Anatomy : — No septa are visible in front of 5/6, which is very thin ; none 

 are notably thickened, though 6/7, 7/8, and 8/9 are slightly so. 



The gizzard, in segment v, is large, long from front to back, cylindrical, and 

 rather soft. The intestine begins behind the prostates, in segment xx. 



The last heart is in segment xiii. 



The nephridia end in the same line. 



Testis sacs are present in segments x and xi. In segment xi they lie beneath 

 the seminal vesicles, to which they are adherent, though it does not seem that their 

 cavities are continuous ; the membrane which constitutes the sac is fine, and rather 

 indefinite, and there is some matting together of all the structures, including the 

 hearts, as if all were enclosed in organizing connective tissue. In segment x the con- 

 dition is similar ; the testis sac is adherent to the seminal vesicle, which spreads over 

 it from the segment behind. 



