v] RELATIVE FREQUENCY 87 



goes, to the Auckland and Campbell islands. Dino- 

 driloides with two species is also limited to New 

 Zealand and to the North Island. MaoridrUus with 

 some ten species is another native and restricted 

 genus. So too is the allied Plagioehaeta with 

 numerous setae on each segment but with the 

 alternating and single nephridial pores of MaoridrUus. 

 There are several species of Plagioehaeta of which 

 one has been lately regarded by Dr Michaelsen as 

 really falling within the otherwise Indian genus 

 Hoplochaetella, while for another he has formed the 

 genus Pereiodrilus. Neodrilus with but one species 

 N. monocystis is another peculiar New Zealand genus. 

 The family Octochaetinae contains only four genera, 

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

 limited to New Zealand, while OctocJiaetus has about 

 five representatives. Hoplochaetella (if Dr Michael- 

 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 Megaseolides (which includes 

 Benham's genus Tokea), perhaps seven species of 

 Dlporochaeta, and two other species which Michael- 

 sen has removed from the genus Diporochaeta and 

 placed in Spenceriella. One Plutellus (which how- 

 ever may have been introduced) completes the New 

 Zealand Megascolecines. We have therefore in this 

 part of the world fifteen genera including between 



