285 



the town gardens being now solely occupied bv the European 

 species. 



The Liimbricidce are naturally at the present day conhned 

 to the PaLTsarctic region, and they are strictly analogous in 

 dominance and distribution to the moUuscan race Bclugona 

 Siphonadenia , and although representatives of this group are 

 found in Eastern Canada, etc., which Mr. Beddard considers 

 may have been artificially introduced, vet the species of 

 Heliodrilus which are found there are amongst the earliest 

 evolved and most wideh^ spread representatives of the race, 

 and it is not unlikely they have spread there in the ordinary 

 course of natural diffusion, in company with certain species 

 of Helix, etc., which are also assumed to have reached Eastern 

 North America by means of the land connection which formerly 

 existed across the North Atlantic. 



The Mcgascolecidœ, as represented by its highest and most 

 recently developed group, Pheretima, also possesses in a striking 

 degree the power of colonisation anywhere except in regions 

 dominated by the Lumbricidcv. The Mcgascolecidœ are a charac- 

 teristically Eastern group, and almost precisely correspond 

 with the Euadeniate mollusca in their relative dominancy 

 and geographical range, the genus Pheretima constituting the 

 rearmost of the retreating group, its territory being invaded 

 by the stronger and later developed Lumbricidœ. 



The Megascolecidœ, like the molluscan Euadenia, ha\'e also 

 crossed the Aleutian bridge and travelled southwards along 

 the shores of the Pacific. The genus Pheretima, so charac- 

 teristic of China, etc., is represented by the closely allied forms 

 Plutellus and Megascolides, belonging to the Megascolccinœ, 

 the same group of which Pheretima is the most modern repre- 

 sentative. 



In tropical Africa, the Mcgascolecidce are represented by 

 Eudrilidce and Dichogaster, two quite characteristic groups. 



The Geoscolecidœ- are quite unknown in Australia, and though 

 regarded as comparatively modern, are destitute of dorsal pores, 

 the absence of which, as one of the indications of their originally 

 aquatic life, bespeaks a high antiquity for the family. They are 

 especially characteristic of Central and South America, and are 

 found in South Africa, Madagascar, and certain parts of India 



