V] RELATIVE FREQUENCY 87 



goes, to the Auckland and Campbell islands. Dlno- 

 driloides with two species is also limited to New 

 Zealand and to the North Island. Maoridrilus with 

 some ten species is another native and restricted 

 genus. So too is the allied Plagiochaeta with 

 numerous setae on each segment but with the 

 alternating and single nephridial pores oi 3Iaorldrilus. 

 There are several species of Plagiochaeta of which 

 one has been lately regarded by Dr INlichaelsen as 

 really falling within the otherwise Indian genus 

 Hoploclmetella, while for another he has formed the 

 genus Perelodrilus. Neodrllus with but one species 

 N. monocystis is another peculiar New Zealand genus. 

 The family Octochaetiuae contains only four genera, 

 of which one, viz. Dinodrilus (Avith four species), is 

 limited to New Zealand, while Octochaetus has about 

 five representatives. Hoptochaetdla (if Dr Micliael- 

 sen's surmise referred to above be correct) has one 

 species in New Zealand. The Megascolecinae are 

 less numerous than the Acanthodrilinae, but there are 

 ten species of the genus 3Ie(jascolides (which includes 

 Benham's genus Tokea), perhaps seven species of 

 Dlporocliaeta, and two other species which Michael- 

 sen, has removed from the genus D'qmwchaeta and 

 placed in SpcHceriella. One Pliitellii)^ (which how- 

 ever may have been introduced) completes the New 

 Zealand JMegascolecincs. We have therefore in this 

 part of the world fifteen genera including between 



