84 EARTHWORMS AND THEIR ALLIES [ch. 



Megascolecinae. Of the genus Pheretima there are 

 two species which may or may not be truly indigenous. 

 Of Plutellus there are forty species ; there are over 

 thirty of Diporochaeta, while Notoscolex (with which 

 Dr Michaelsen associates Digaster, Didymogaster, 

 Perissog aster) includes more than forty species, 

 Fletcher odrilus has but one species, Megascolex has 

 seventy species, Woodwardia sixteen, Spenceriella 

 five, and Megascolides seventeen. There are four 

 species of Perionyx which were at one time regarded 

 by Michaelsen as necessitating a new but allied genus 

 Perionychella ; the two are now merged. Thus there 

 are not far short of 150 species and eleven genera 

 represented, of which only two are limited to 

 Australia. 



Having completed the survey of the central and 

 southern land masses of the globe we next direct 

 attention to the northern land masses, viz. North 

 and Central America on the one hand, and Europe 

 and northern Asia on the other. With regard to 

 America we find besides many species of Lumbri- 

 cidae the genera Notiodrilus, Microscolex among 

 the Acanthodrilinae, Megascolides and Plutellus of 

 the Megascolecinae, no member at all of the Octo- 

 chaetinae, a considerable number of species of 

 Ocnerodrilus and sub-genera belonging to the Ocnero- 

 drilinae, a good many species of Dichogaster and at 

 least one of Trlgaster among the Trigastrinae, while 



