126 DR. J. STEPHENSON ON THE MORPHOLOGY, CLASSIFICATION, 



having purified our material in this way, Michael'sen holds that 

 we have in the Oligochaeta a, group which is capable of yielding 

 results for palaaogeography second to those of no other group in 

 importance and certainty ; the worms cling to the soil in the 

 most literal way, can only make use of the earth in their wander- 

 ings, and b} r the facts of their present distribution can thus 

 demonstrate in the plainest manner the existence of land 

 connections where, it may be, there is now only a wide stretch of 

 ocean. 



(2) The Facts of Distribution and their current Explanation. 



The material which is available for use in the following 

 discussion is derived from the following groups : — The sub- 

 families Megascolecinas, Octoeluetina?, and Trigastrinaa of the great 

 family Megascolecidse ; the family Moniligastridas ; and scarcely 

 anything else. 



(a) The Megascolecince. For the phylogenetic relationships of 

 the genera of Megascolecinae the previous article and its text- 

 figure may be referred to. 



Diplotrema, from which the subfamily takes its origin, occurs 

 in Queensland and New Caledonia. Plutellus is found in Ceylon, 

 S. India, and the E. Himalayas; in Australia and Tasmania; 

 several species occur in the western part of N. America. Mega- 

 scolides occurs in S. India, in W. India, and in the E. Himalayas ; 

 in Australia and Tasmania ; and it has one species in western N. 

 America. Notoscolecc is found in the Indian region mainly in 

 Ceylon, but also in S.India and in the E. Himalayas; outside 

 India it occurs in Australia and New Zealand . Megascolex is found 

 especially in Ceylon, to a somewhat less extent in S. India, and 

 hardly anywhere else in the Indian region ; outside India it is 

 found in Australia, Tasmania, the N. Island of New Zealand, and 

 Norfolk I. (between New Zealand and New Caledonia). Pheretima 

 is a genus of which many members have wandered widely ; its 

 proper home, however, is S.E. Asia and the neighbouring islands — 

 the whole of the Malay Archipelago ; from Burma on the one 

 side it reaches to Japan on the other ; a few endemic species are 

 found in India proper, but they hardly entitle India to be con- 

 sidered as part of its proper home ; one species is perhaps endemic 

 in Queensland, and perhaps one in the Comoro Is. Diporochceta 

 is only represented by one species in India, and the record is an 

 old one : no locality is given, but it was probably found in S. 

 India; the headquarters of the genus is Victoria and Tasmania; 

 species are also found in Queensland, New Zealand, and (one 

 species) on the Chatham Is. (east of New Zealand). Perionyx occurs 

 as the dominant genus in the E. Himalayas, and is also scattered 

 over India generally ; it occurs also in Victoria, Tasmania, and 

 the Auckland Is., and one species is found in Sumatra and Java, 

 (as usual, peregrine species are omitted from this review). 



