AND ZOOGEOGRAPHY OF INDIAN OLIGOCUJETA. 127 



Woodwardia is found in Ceylon and S. India, and in Burma ; also 

 in Australia and in Java. Comarodrilus is purely Indian — there 

 is only one species, found in the extreme south. Spenceriella, a 

 small genus, occurs in S. India and Victoria. 



A few other small genera of terrestrial Megascolecinpe, 

 characterized by an increase in the number of gizzards, do not occur 

 in India; two are Australian, one is common to Australia and 

 New Zealand, and one occurs in the Philippines and Moluccas. 



It Avill be seen that nearly the whole of the Indian genera (all 

 except the small genus Comarodrilus) are represented in Australia ; 

 a number are found also in New Zealand, a few in the islands 

 near New Zealand, and a few in the islands of the Malay Archi- 

 pelago. 



The conclusion drawn from the occurrence of the parent genus 

 Diplotrema in Queensland is that the subfamily took its rise from 

 somewhere in this region, which is not very far from the centre 

 of the area now inhabited by the subfamily. The descendants 

 have travelled further afield — towards India, towards Tasmania, 

 towards New Zealand and the neighbouring islands, and north- 

 ward throughout the Malay Archipelago to Japan. And of 

 course the important point is that they must have travelled 

 by land. The reason for the absence of so many of the genera 

 from the islands intervening between Australia and India 

 is that here the mighty genus Pheretima has crushed all com- 

 petitors ; it is the youngest, most highly specialized, and most 

 vigorous genus of the subfamily ; it is still spreading, many species 

 are among those most commonly introduced by man, and they 

 show themselves most successful colonists. 



Michaelsen does not, however, assume the prolonged existence 

 of a broad land connection between the regions mentioned. The 

 relations were much more complicated, and were often changing. 

 Perhaps there was not a complete bridge at any time ; the 

 normal condition of the region intervening between Australia 

 and New Zealand on the one hand and India on the other was that 

 of an archipelago, which extended to Ceylon and S. India over 

 the present Bay of Bengal. The boundaries of the islands often 

 changed : sometimes they joined, sometimes they separated, — 

 and no doubt in a different place ; and in this way paths 

 became available for the continued expansion of the various 

 genera. 



Moreover, since certain Indian genera have such a definitely 

 limited area (certain of those already noticed being confined to 

 S. India, Perionyx being chiefly an inhabitant of the Himalayan 

 region, and Eutyphceus, to be mentioned subsequently, being 

 confined to the Gangetic plain), India itself was split up into 

 a number of large islands. Thus the Malay Archipelago is the 

 only remaining part of a lai'ger archipelago which existed in 

 the early Tertiary, of which the middle part is submerged, and 

 the "Western has consolidated to form the present India. The 



