532 Ml-. C. li. Nara}aini Rao on tlie Anatomy of 



ridges appear to be coraposed of a cord of small spherical cells 

 witli longitudinally disposed umscle-fibres, the whole of the 

 ridge being compactly held by a thin cuticular pellicle. 

 The entire pouch perhaps represents the greatly modified 

 atrial tubules of Moniliyaster perriei'i — a view \\hich in some 

 measure receives support from the fact that these ridges are 

 canalised in the case of forms which are just developing the 

 spermathe'cal apparatus, and the peritoneal wall encapsuling 

 them is still thin and devoid of muscle-fibres (PI. XVIII. 

 figs. 10 A & ]0i). The more complete organisation of the 

 peritoneal investment into the atrial pouch must synchronise 

 with the degeneration of th.e tubes into incomplete ridges. 



The Nephridiul System. — The vesicle in this species is non- 

 glandular, unlike the other examj)les described in this paper, 

 and hence has the same structure as that described in 

 D. grandis (PL XVI. fig. 5). It is quite transparent, being 

 composed of a few circularly disposed muscie-libres, and, iu 

 the case of anterior somites in the front of the clitellum and 

 even iu some examples behind it, the vesicle opens by a broad 

 circular aperture into tlie respective coelomic chamber. A 

 glandular vesicle is not, however, uncommon even iu this 

 s()ecies and then they are white and j)erfectly o[);tque. The 

 nephridial lobes and their relation to the other structures' 

 are so different in this and the other species described in 

 this paper from the figure of D. yrandis given by Bourne 

 (pi. xxvii. fig. 42, Q. J. M. Sci. vol.xxxvi.), that a few words 

 respecting the renal organs will not be inappropriate here. 

 The two vesicles form nearly a complete ring round the 

 alimentary canal, almost meeting dorsally, but extending 

 only lialfway ventrally below the intestine. From the lower 

 half of its stem is given off the slightly coiled muscuhir duct, 

 which runs outwards to open on the seta-line cd. Among 

 the glandular lobes we recognize the twisted and the luoped 

 ones. There are two of the former kind, one being longer 

 than the other, both ventral to the alimentury canal, and the 

 longer tuisted k-bes on each side are only separated by 

 the nerve-cord. There are tliree loojjcd lobes : two of them 

 are in close relation to the sides of the alimentary canal on 

 the inner side of the vesicle^ and the third more or less 

 attached to the muscular tube, and hence on the outer side 

 of the vesicle. The funnel-tube enters the main glandular 

 mass at the point where the inner looped and the twisted 

 lobes diverge, and the duct of the funnel-tube also divides, 

 entering respectively tl.e two main divisions of the nephridial 

 structure. In regard to the histological structure of the 

 diti'erent parts, excepting the neplirostome, which is same as 



