88 THE WANDERINGS OF ANIMALS [CH. 



by other groups of animals. Unfortunately there 

 are no fossil data. The following points are in favour 

 of the importance of earthworms : they are in their 

 welfare and possibility of spreading dependent upon 

 the existence of vegetable mould ; they cannot stand 

 sea-water, and their mode of dispersal depends 

 entirely upon their own powers of locomotion, which 

 are considerable; accidental, occasional lifts of the 

 worms, or of their cocoons, are practically excluded, 

 except by human agency since prehistoric times. 

 There are for instance in the Sandwich Islands more 

 than a dozen kinds of earthworms, of genera, which 

 are not restricted to these islands. On the contrary, 

 some of them have a very wide distribution. Conse- 

 quently these worms must have come from elsewhere, 

 and speaking geologically, not so very long ago. 



A very different case is presented by various 

 Antarctic islands, e.g. Kerguelen and Marion to the 

 south-east of the Cape. Their characteristic worms 

 belong to the presumably ancient Acanthodrile group, 

 and are, according to Beddard and Michaelson, quite 

 indigenous, since they are all different as species and 

 found nowhere else. The further contention that these 

 islands are not truly oceanic but the remnants of 

 a former much larger mass of land may also be valid, 

 but it does not follow that this land was part of 

 a former northern extension of the Antarctic con- 

 tinent. Like the fish-genus GalcLxias (cf. p. 95) 



