23^ J- Stephenson: Two Oli^ochxte Worms. [Vol. I, 



rounded cornua. It is much easier to see in some cases than in 

 others, but is never very prominent. While the two forms shown 

 in fig. 4 may certainly both be recognised in different animals, the 

 difference may possibly be explicable, partly at any rate, b}^ a 

 difference in the degree of protrusion or retraction of the pro- 

 stomium ; the effect of protrusion might be to double back the 

 ends of a normally oval-shaped, transversely-placed ganglion. I 

 have, however, no observations to show whether this is so, as it is 

 impossible to follow the shape of the ganglion during an}^ move- 

 ment of the animal. There are no pharyngeal commissures and 

 no ventral cord. Fine hairs, perhaps sensory, are distributed 

 over the whole body. On the under surface of the prostomium 

 are certain cells which stain a deep blue on the addition of a little 

 methylene blue to the water in which the animal is being examined ; 

 these may perhaps be special sense-cells. 



No genital organs or clitellum were seen. 



The above described species of ^olosoma appears to have 

 most affinity with ^. headleyi, Beddard, of which I transcribe the 

 specific characters as given in Michaelsen's Oligochceta. " Kopf- 

 lappen breiter ah die folgenden Segm. Oeldrilsen leuchtend gmn, 

 manchmal ins Blduliche spielend. Borsten sdmtlich lang, haar- 

 formig, S-formig geschweijt. Gehirn hinten grade abgestutzt (?). 8-9 

 Nephridien-paare, erstes hinter dem i Borstenhundelpaar. Mdssig 

 gross [L. ca. 2*5 mm. ?)." 



The question of colour and of the site of the element of blue 

 in the species here described has been entered into above, and 

 also the question of the shape of the cerebral ganglion, about 

 which in M. headleyi there would appear, from Michaelsen's note 

 of interrogation, to be some doubt ; I do not, however, think that 

 in any case its shape could, in the species now described, be said 

 to be " cut off straight behind." A greater number of nephridia 

 is given for M. headleyi than those I have been able to count. The 

 length is perhaps not a very important point. 



There remains only the question of the setae. I cannot find 

 that in this species there is an}^ S-shaped curve ; they may, of 

 course, be temporarily curved through the resistance of the water 

 or pressure of the cover-glass ; but examined at rest, without a 

 cover-slip, such a curve, if present at all, is of the Yoxy slightest, 

 and is not S-shaped. 



The general resemblance, however, of this form to JS. headleyi 

 would appear to be considerable, and it may be possible to unite 

 the two under that name. 



The above species will doubtless receive formal description 

 and a specific name from Dr. Michaelsen in his Monograph on the 

 Indian Oligochgeta, soon to appear ; as, however, it is difficult to 

 be certain of details of internal anatomy in preserved specimens, 

 it seemed worth while to give a description based on examination of 

 the living animal ; so that, although appearing before Dr. INIichael- 

 sen's work, the above notes are really supplementary and logically 

 posterior to it. 



