450 



OLIGOCHAETA 



A careful tabulation of Fletcher's results (from above table) does not perhaps 

 altogether support this proposed division of the genera ; but in only a few cases 

 has he noted the form of the spermiducal glands, which is, I believe, of systematic 

 importance. Out of the twenty -three species to which he .has paid attention, five 

 conform to the rule of association which I have endeavoured to lay down above; 

 four are apparently exceptions ; of these four C. rusticus has diffuse nephridia, 

 lobate glands, but the last pair of hearts are in xii ; I have already referred to 

 M. gippsland icus as another exception resembling M. australis ; M. tasmanianus 

 has paired nephridia and tubular glands, but the last pair of hearts are in xiii ; 

 C. mediterreus has paired nephridia with lobate glands, the last pair of hearts in 

 xiii ; of the remaining species, three are peculiar in having three pairs of nephridia 

 per segment like one of the species described by Spencer ; so I put them out of 

 the comparison, reserving a distinct generic title for them. There remain eleven 

 species which are not sufficiently described by Fletcher ; in nine of them the 

 condition of the nephridia and the segment occupied by the last pair of hearts is 

 noted ; five of these agree with the proposed division ; G. fletcheri, described by 

 myself, has paired nephridia with lobate spermiducal glands. On the whole, therefore, 

 it seems to me to be justifiable to retain the two generic names Gryptodrilus and 

 MegascolifJes, but to sort the species rather differently. I put those with tubular 

 glands on one side, reserving the name Megascolides for them ; the species with 

 lobate glands I call Gryptodrilus. 



In addition to these there remain a number of Australian species which Fletcher 

 has relegated to three genera — Bigaster, Perissogaster, and Didymogaster ; the name 

 of the latter must in any case, as Fletcher has pointed out, be dropped since it has 

 been already applied to a genus of insects. These three genera contain between 

 them only seven species ; in the following table the chief characters of these seven 

 species are set forth. 



