368 W. BLAXLAND BENHAM. 



" feuillets blancs " as forming part of the sperm-duct, for it 

 would, says he, give such an enormous length to it. 



I may mention that in Perrier's species the sperm-duct, 

 which is represented as a comparatively thin coiled duct, 

 appears to pass through a mass of isolated white leaf-like 

 structures set round the duct as an axis. A microscopical 

 examination of these " feuillets " showed that they consist of 

 a very fine coiled duct surrounded by a thin membrane (his 

 fig. 83), and I think there can be no doubt, from the condition 

 present in M. indicus, that this duct in the '^ feuillet'Ms 

 part of the sperm-duct itself, and not an appendix thereto. In 

 other species, so far as descriptions go, the duct is not of so 

 great a length. The cells lining the duct are striated as in 

 other worms (fig. 13), but I have never been able to detect 

 hitherto the boundaries of the cells ; here, however, they are 

 very plain, and the cells large. In many earthworms the 

 nuclei are flattened, but here, as in aquatic forms also, they 

 are spherical. 



In M. indicus the greater part — nearly the entire length — 

 of this fine, convoluted sperm-duct lies in Somite ix below the 

 sperm-sac (figs. 4, 5). It passes through the septum near the 

 body- wall, which it enters, traverses the short distance 

 between this septum and the prostate, embedded in the longi- 

 tudinal muscle, and enters the atrial wall (prostate) at its 

 anterior end (fig. 5) ; passes along the dorsaWall of the prostate, 

 perforates the glandular coat, and opens into the atrial cavity 

 at the apex of a slight prominence in the wall (figs. 5, 8) . 

 This condition of the duct is very similar to that described by 

 Rosa for Desraogaster doriae, and so far as the praeseptal 

 portion is concerned agrees with Michaelsen's description of 

 M. japonicus. 



The prostate is a hemispherical structure occupying the 

 greater part of the length of Somite xi, at the anterior margin 

 of which it opens to the exterior; it also encroaches to a slight 

 extent on to Somite x, to which it probably belongs morpho- 

 logically. 



It is about half (linear) the size of the sperm-sac, larger 



