2o8 Records of the Indian Museum. [Vol. VI, 



(segment vi). The arrangement therefore corresponds to the 

 accepted numbering of the segments in Chaetogaster, according to 

 which the second setal bundle is assigned to the sixth segment. 

 Behind this the ganglia have the usual discrete arrangement. 



On the clitellum, cf. my remarks in Rec. Ind. Mus., vol. i, 

 pt. 3, pp. 249—51. 



Nais pectinata, Stephenson, var. inaequalis , var. no v. 



In Rec. Ind. Mus., vol. v, part 4, I recorded a new species 

 of Nais, the peculiarity of which consisted in the possession 

 of ctenate needle-setae in the dorsal bundles. The same material 

 from which this species was obtained was shortly afterwards 

 returned to me, in order that I might pick out a number of 

 specimens for separate preservation in the museum. During this 

 re-examination I came across a single specimen of a Nais in 

 which the dorsal needles, though ctenate, differed considerably 

 from those found in the ordinary .V. pectinata ; as however in 

 other respects the specimen closely resembled the latter, I 

 describe it here as a varietv. 



Pig. 2. — Nats pectinata var. inaequalis : a needle-seta belonging to a dorsal 

 bundle ; distal portion only. 



Segments 50, plus an undifferentiated growing region at the 

 posterior end. No eyes. 



The dorsal setal bundles, beginning in segment vi, consist 

 usually of one hair-seta and one needle ; occasionally of one 

 hair and two needles, or of two setae of each type; in the last 

 case one of the hair-setae is much shorter than the other. The 

 hair-setae are usually about 250 /■ long, the shorter ones however 

 about 100 fx ; both are quite smooth. The needle-setae are 67 — 

 75 /* long, with a slight sickle-shaped curve which includes the 

 distal third of the shaft ; there is no nodulus The end is ctenate ; 

 but the tooth of the comb which lies towards the inside of the 

 curve of the shaft is very much stronger, and considerably longer 

 than the others (fig. 2) ; the outer tooth is also slightly larger 

 than the intermediate ones. There may be two, three, or four 

 small intermediate teeth; in one case there were none, the seta 

 being thus merely bifid at its end. 



The ventral setae begin in segment ii, and are in bundles 

 of three or four; the length is 60 — 65 /< throughout the body. 

 These bundles may be divided into two groups, an anterior, com- 

 prising those of segments ii — v, and a posterior, from segment vi 

 onwards. In the anterior bundles the setae are slighter in form, 

 and less strongly curved, the distal prong of the forked end 



