260 DK. W. B, BENHAM OX [NoV. 15,. 



depends on the laAv of priority ; and there can be little doubt but 

 that Megascolides australis is the " type " of Megascolides M'Ooy ; 

 but it does not seem quite so clear as to whether the word Roto- 

 scolex or Gryptoclrilus should be retained to apply to the other 

 genus. But this thorny matter of nomenclature I regret that I 

 have not time to discuss thoroughly. 



Having thus cleared the ground, satisfactorily as it seems, of 

 the meganephric species, there remain the large series of micro- 

 nephric species to be dealt with ; and it becomes a question whether 

 Michaelsen's characters are good, viz. : 



(a) Absence or presence of meganephridia posteriorly ; and 

 (6) A limited number (tAvo pairs) or a greater number (up tO' 

 five pairs) of spermathecse. 



In regard to the first, it is admitted that in many species we 

 are ignorant as to whether the large nephridia are or are not 

 present. 



In the second case, in other genera — e. g., Pheretima and Mega- 

 scolex — the number of spermathecse has not been used as a generic 

 character*. 



Since, therefore, the seven species of New-Zealand worms here 

 described agree very closely with one another, and except in one 

 respect differ from those species referred to Megascolides by 

 Michaelsen, and since, too, I am not in a position to rearrange 

 the generic characters of these allied genera, it seems to me better- 

 to erect a new genus. It may be that it is only of subgeneric 

 rank ; but for the present less confusion will arise, I think, if we 

 regard it as a distinct genus. 



The genus Tokea differs from Megascolides, as defined by 

 Michaelsen, in the following points : — 



{a) The limited extent of the clitellum, in which only 4 or 5 

 segments are involved, whereas his minimum is six. 



(&) The widely separated chtetse, of which the coupling is not 

 recognisable. 



(c) The form and position and size of the prostate. 



(d) The position of the point of entrance of the sperm-duct 



into the prostate-duct. 



(e) The existence throughout the body of nephridial funnels, 



although in the greater part of the worm these have no 

 connection with the nephridia. 



These are truly small points of difference on which 'to form .a. 

 new genus ; but not smaller than that on which Megascolides is 

 distinguished from Notoscolex, viz., the presence in the former of 

 meganephridia in the hinder segments of the body f. In my 

 opinion, this is by no means a good line of distinction ; and even 



* The same remark applies to the position of the last heart, utilised in diagnosing- 

 the o-enera by Beddard ; for in Flagiochmta and Octoclicetus, as in ToTcea, we lind 

 species in which it is in the 12th, and others in which it is in the 13th segment. 



f Or, 3IaoridriIus from Notiodriliis, in having nephridiopores alternate, instead 

 of in line 



