192 AFFINITIES OF FAUNA. [CH. IV 



peculiar species. In all 75 species of Insecta were 

 identified, and out of these 27 were peculiar species, 

 including the two genera above referred to. The fresh 

 waters of the islands contained, besides the Planorbis 

 mentioned, an Ostracod and a Gammarus, both believed 

 to be peculiar. There was a total lack of fresh-water 

 fish and of fresh -water as well as terrestrial Amphibia. 



One earthworm is known from Fernando Noronha, 

 identified by Mr Benham with the widely ranging but 

 especially Neotropical Pontoscolex corethrurus. 



The most salient features therefore in the fauna of 

 these islands are the total want of mammals of an 

 indigenous character, of fresh-w r ater fish, and of Am- 

 phibians, the rarity of reptiles, and finally the large 

 number, speaking relatively to the total of course, of 

 indigenous forms peculiar to the island. Of these how- 

 ever but few are of new generic types ; but this statement 

 as in the case of the fauna of Kerguelen, to be dealt 

 with presently, must be tempered by reflection as to the 

 different ideas which different naturalists have of the 

 value of a genus. As to the affinities of the fauna it is 

 noteworthy that the West Indies enters largely into the 

 matter ; there is not, as might be assumed at first, an 

 absolute likeness with the nearest coasts of South America. 

 But the winged fauna, Mr Ridley points out, whether 

 they are endemic or have a wider distribution, have a 

 South American facies which is quite unmistakable. 



