5 88 Memoirs of the Indian Museum. [Voi,, V, 



small flat wing above its base, and the wings of the ventral cirrus are larger. The 

 posterior lobe of the dorsal fillet is greatly enlarged, displacing by its growth the 

 median ligule. The ventral setigerous lobes are also greatly enlarged and flattened, 

 and the ventral ligule is directed downwards. The 58th foot is much the same, but 

 it is smaller, and has a larger proportion of the normal setae. 



The eggs escape from the body cavity through the tips of papillae on the ventral 

 surface near the base of the feet. The swimming setae (fig. 8r) are modified homo- 

 gomphs. They are very transparent. The end of the shaft is cup-shaped, with an 

 anterior spinous projection. The blade, which is minutely serrate, increases in width 

 to near the tip, and then narrows suddenly to a sharp point. 



The two female Heteronereids were found under stones on the shore. Another 

 Heteronereid was taken on the surface of the lake, where it was gyrating in a spiral 

 course. It is a fully developed Heteronereid, but the sexual products have been 

 completely extruded. It is probably a male, as it differs in several important point s 

 from the specimen just described. It is small in size, being only 16 mm. long, but 

 it consists of 72 setigerous segments. The eyes are very large, and the head is 

 deeply pigmented, the wdiite patch, which occurs in all other specimens, being 

 absent. The anterior end of the body is dorsally very deeply coloured with metallic 

 brown pigment, and is without the characteristic pattern. The tentacular cirri are 

 unusually long. 



The anterior 19 pairs of feet are unmodified, except that the 19th has a single 

 swimming seta in the dorsal division, and that the dorsal setigerous division is in 

 all the feet fused with the median ligule (fig. 8l). In the 20th foot the lobes are not 

 altered, but the dorsal division contains only swimming setae, and a few of these are 

 also in the ventral division. The only unchanged setae are the two thick falcate 

 heterogomphs of the upper ventral group. In the 25th foot only one thick falcate 

 seta remains. The setigerous lobes are enlarged and flattened, and the ventral cirrus 

 has basal wings. In the 30th foot (fig. 8m) the median ligule, to which the dorsal 

 setigerous lobe is fused, is enlarged and flattened. The ventral setigerous lobes are 

 also flattened, the anterior one being large and foliate. The 18 posterior feet are not 

 modified, and have only normal setae. The dorsal cirrus is very long, and the ven- 

 tral cirrus has increased and projects beyond the ventral ligule. The spines are very 

 thick and dark. 



A specimen taken on the shore seems to represent a stage in the development of 

 the last described form. It is a slender worm, 22 mm. long, with 62 setigerous seg- 

 ments. The body cavity is full of sperm morulae in an early stage of development. 

 The head of this specimen is shown in fig. 8b. It has very large eyes, and the 

 tentacular cirri are unusually long. In both these points it resembles the male Hetero- 

 nereis. The colour, however, is normal. The most exceptional character of this 

 specimen is that in a few of the posterior feet the dorsal ligule decreases very much 

 in size (fig. 8h), a character noted in no other individual of this species. The 

 jaws of this specimen have 10 teeth. 



It is remarkable that all the partially or completely metamorphosed Hetero- 



