I9I4-] J- Stephenson : Oligochaeta from Northern India. 333 



the last of these newly formed segments must develop a dorsal 

 bundle as well as a ventral ; in one case this was distinctly seen to 

 have occurred. In general in the Naididae the cephalized segments 

 (those distinguished by the absence of dorsal setae) are those 

 which are produced in the budding zone (12) ; here the budding 

 zone produces one of the body segments also. 



The prostomium is blunt and rounded. 



The anal funnel at the posterior end of the body can be 

 widely opened, and its margin everted to a much greater degree 

 than is shown in Bousfield's figure (2, fig. 18). There is a pair 

 of palps, and three pairs of gills. The posterior and middle pairs 

 of gills constitute finger-like projections arising from within the 

 funnel ; the anterior gill on each side is the folded and projecting 

 margin of the funnel, and disappears, or rather appears merely as 

 a fold in the margin, when the funnel is fully everted. The 

 posterior and middle pairs are about "36 mm. in length, or twice 

 the diameter of the body at its hinder end ; and the palps are of 

 about equal length or in some cases rather shorter. All the gills 

 are vascular, and show a number of bipolar or stellate cells, 

 arranged at intervals, crossing the cavity of the gill-process (c/. 

 Dero limosa, sup.). 



The dorsal setae begin in segment v ; each bundle consists of 

 one capillary and one needle seta. The hair-setae are on an 

 average 200iu in length, and are quite smooth. The needles are 

 60-62M long ; the nodulus is situated rather more than one-third 

 of the length of the shaft from the distal end ; the free extremity 

 is bifid, and the shaft has a slight sickle-shaped curve in its distal 

 portion. 



The ventral setae are usually four per bundle, rarely five; 

 posteriorly the number diminishes to three, and in a number of 

 the terminal segments to two only. The setae of the anterior 

 bundles (segments ii-iv) differ from those in the rest of the body. 



In the first few segments (ii-iv) their length is about 75/x, 

 and breadth 2'5/a. The distal prong of the fork is ij times as 

 long and | as thick at the base as the proximal prong. The 

 nodulus is, in the innermost seta of a bundle, proximal to the middle 

 of the shaft, thus : — distal to nodulus : proximal to nodulus : : 

 7:5. In the middle setae of a bundle, the nodulus is at the middle 

 of the length of the shaft ; and in the outermost it is also at the 

 middle, or very slightly distal. 



In the remaining segments (v onwards) the length is 62-66/^, 

 and the thickness 3/^. The prongs of the fork are equal in length, 

 but the proximal is twice, or even two and a half times, as thick 

 at its base as the distal. The nodulus is usually distal to the 

 middle of the length of the shaft, but its position varies in the 

 same way as in other species of Dero and Aulophorus (10, and cf. 

 Dero limosa, ant.); that is to say, it is more distally situated in 

 the outer setae of a bundle than in the inner. 



Thus in the innermost seta of a bundle the nodulus was 

 found to be very slightly proximal to the middle of the shaft; in 



