102 EARTHWORMS AND THEIR ALLIES [CH. 



P. peregrinus is known from Australia and also from 

 Sumatra, so that that species need not concern us 

 in enumerating those which are possibly endemic. 

 In fact it is only P. pentaeystis and P. voeltzkovi 

 which may be really Mascarene. 



Another peregrine genus belonging to the sub- 

 family Acanthodrilinae is Microscolex. But the limits 

 of this genus may be regarded as at present rather 

 uncertain. And this difficulty somewhat affects the 

 bearing of the facts to be related, though it hardly 

 affects the value of the facts themselves. Dr Michael- 

 sen referred to the genus in his great work seven 

 well-defined species, and four others not so plainly 

 distinct. Of these eleven, two are confined to New 

 Zealand, four to North and Central America, one to 

 Hawaii, one to Madeira, one to Algeria, while the 

 remaining two are found pretty well over the whole 

 surface of the world. More recently the same 

 authority has somewhat extended his view of the 

 generic characters, so as to include a number of 

 forms found in Patagonia, Cape of Good Hope, and 

 the antarctic region generally, while he has lumped 

 together into two species only, viz. M. pliosphoreus 

 and M. duhlus, the eleven forms just mentioned, 

 which species therefore are absolutely world-wide 

 in range, and thus form an excellent example of a 

 peregrine form. These species moreover differ from 

 Pontoscolex and some others in that they have been 



