788 CONTRIBUTION TO AUSTRALASIAN OLIGOCH^TA, I., 



Remarks. — Until the last few years, the genus Phreodrilus, 

 founded by Beddard in 1891, was represented by a single species, 

 P. subterraneus, and was regarded as an appendix to the family 

 Tubificidce. As quoted by Benham, "Michaelsen gave an extended 

 interpretation to that genus so as to include the four species of 

 South American worms originally placed by Beddard in a distinct 

 genus, Hesperodrilus; this enlargement of the genus has been 

 rendered necessary by the discovery of a freshwater worm in 

 Kerguelen, which, in certain respects, bridges over the anatomical 

 gap between the two genera as formulated by Beddard, just a3 it 

 serves as a stepping-stone in the geographical distribution of the 

 genus as now extended." 



In 1904, Benham described three new species of Phreodrilus 

 from the New Zealand lakes, and, in 1907, he instituted a new 

 genus, Phreodriloides of the same family, on a single specimen 

 obtained from the Blue Lake, Mt. Kosciusko, by Prof. David 

 and Mr. Hedley. 



This extension of the area of distribution of the Phreodrilidce 

 is very interesting, and more so now, in the further extension of 

 the same into more temperate regions and conditions in the 

 Australian area. In connection with this family, the conditions 

 of habitat of the various genera are of some value from a phylo- 

 genetic standpoint. Phreodrilus subterraneus was obtained in 

 subterranean wells; P. lacustris was obtained in Lake Wakatipu, 

 at a depth of 300 to 1,000 feet; and P. mauiensis in Lake Mana- 

 pouri, at a depth of 150 to 500 feet. The locality of occurrence 

 of the South American and Kerguelen Island forms is also of 

 interest. Phreodriloides was obtained in the Blue Lake, Mt. 

 Kosciusko, at a height of 6,000 feet above sea-level, in a depth 

 of 35 feet, the temperature being 44° Fah. These facts, in con- 

 junction with the peculiar condition under which Astacopsidrilus 

 (gen.nov.) is found, would seem to indicate that the family is 

 constituted by a number of forms which have had to migrate 

 from the field of competition into surroundings and conditions 

 more favourable for the preservation of forms which have found 

 it impossible to carry on the struggle for existence under more 



