400 



ISLAND LIFE. 



[part II. 



an active volcano 8,500 feet high ; and, as already stated, they 

 are situated on a submarine bank with less than 500 fathoms 

 soundings, connecting Madagascar with Africa. There is reason 

 to believe, however, that these islands are of comparatively 

 recent origin, and that the bank has been formed by matter 

 ejected by the volcanoes or by upheaval. Any how there is 

 no indication whatever of there having been here a land-con- 

 nection between Madagascar and Africa ; while the islands 

 themselves have been mainly colonised from Madagascar, to 

 the 100-fa thorn bank surrounding which some of them make 

 a near approach. 



The Comoros contain two land mammals, a lemur and a civet, 

 both of Madagascar genera and the latter an identical species, 

 and there is also a peculiar species of fruit-bat {Fteropus 

 comorensis), a group which ranges from Australia to Asia and 

 Madagascar, but is unknown in Africa. Of land-birds forty-one 

 species are known, of which sixteen are peculiar to the islands, 

 twenty-one are found also in Madagascar, and three found in 

 Africa and not in Madagascar; while of the peculiar species, 

 six belong to Madagascar or Mascarene genera. 



These facts point to the conclusion that the Comoro Islands 

 have been formerly more nearly connected with Madagascar 

 than they are now, probably by means of intervening islets 

 and the former extension of the latter island to the westward, 

 as indicated by the extensive shallow bank at its northern 

 extremity, so as to allow of the easy passage of birds, and 

 the occasional transmission of small mammalia by means of 

 floating trees.^ 



The Seychelles Archipelago. — This interesting group consists 

 of about thirty small islands situated 700 miles N.N.E. of 

 Madagascar, or almost exactly in the line formed by continuing 

 the central ridge of that great island. The Seychelles stand 

 upon a rather extensive shallow bank, the 100-fathom line 

 around them enclosing an area nearly 200 miles long by 100 

 miles wide, while the 500-fathom line shows an extension of 

 nearly 100 miles in a southern direction. All the larger islands 



1 For the birds of the Comoro Islands see Proc. Zool. Soc, 1877, p. 295, 

 and 1879, p. 673. 



