356 Records of the Indian Museum. [Vol. XIII, 



testis segment, and certainly not in any of the subfam. Octochae- 

 tinae. Michaelsen does not seem quite clear what to make of it ; 

 in the generic characters which he attributes to Hoplochaetella (lo) 

 he has '* i Muskelmagen vor den HodenSegm." ; while in the 

 specific diagnosis of H. stuarti he says " Muskelmagen im lo Segm." 

 I think we may fairly suspect an error in Bourne's statement. 



The four pairs of dorso-lateral intestinal caeca may or may not 

 be more than the usual segmental bulgings of the intestinal walls, 

 commonly best marked in the dorso-lateral region, carried to an 

 unusual degree. 



These are the only differences between Perichaeta stuarti and 

 the group of species described below that could possibly be of gene- 

 ric importance ; — I mean, the onl^' differences that unequivocally 

 follow from the description. Michaelsen in his generic and speci- 

 fic diagnoses in the " Tierreich " gives other points, which rest on 

 inference. 



The first of these is the (doubtful, for he queries it) position 

 of the male pore {i.e the ending of the vas deferens, as distinct 

 from the prostatic pores) on segment xviii. Bourne does not men- 

 tion this ; in so far as we can infer anything, I think we must infer 

 the absence of pores on xviii. ; since in his introduction he brings 

 forward the presence of two male pores, on segments xvii and xix, 

 as a distinction between P. stuarti and ordinary species of Peri- 

 chaeta, which have " a pair of laterally-placed male pores in so- 

 mite xviii." 



The second is the position of the spermathecal apertures in 

 furrows y/8 and 8/9. Bourne makes no reference of any kind to 

 the apertures, saying only that the spermathecae are in segments 

 vii and viii. The apertures often are in the furrows just men- 

 tioned in the Octochaetinae, but not always ; m Erythraeodrilus , 

 and in some species of Octochaetus, they are on the segments, not 

 between them. 



The third and most important is the condition of the nephri- 

 dial system. All that Bourne says is, " I have not observed any 

 nephridia." Michaelsen naturally takes this to mean that the sys- 

 tem is micronephric throughout. I hope I shall not be going too 

 far if I suggest that Perichaeta stuarti may have possessed both 

 mega- and micronephridia, and that the meganephridia as well as 

 the micronephridia may have been overlooked by Bourne. It is 

 to be remembered that (i) in the group of species which I describe 

 in the body of the paper the meganephridia only begin in seg- 

 ment XX ; if a similar condition existed in P. stuarti it might not 

 have attracted attention in a dissection of the anterior part of the 

 worm (though I admit that Bourne must have dissected one or 

 more specimens back to at least the level of the hinder ends of the 

 long prostates). (2) Bourne's observations on the nephridia of 

 other species described in the same paper are extraordinarily various ; 

 thus " I have found no nephridia," {Perichaeta lawsoni) ; " there 

 are two pairs of groups of small nephridia opening on the posterior 

 edges of somites vii. and viii," {P. gracilis, — nothing about nephri- 



