THE INSECTS OF ST. HELENA 889 



ncte he recorded two scorpions (Lychas maculatus and L. 

 americanus). These have since been shown to be both forms 

 of Isometrus maculatus, a cosmopolitan species of the tropical 

 and sub-tropical zone. In Europe it occurs only in the south 

 of Spain.* 



The total number of land-shells indigenous to St. Helena 

 is estimated by Mr. Smith as amounting to twenty-seven 

 species. With regard to their origin, he likewise rejects the 

 theory of a possible land connection of the island with either 

 Africa or South America, or, indeed, any other land surface. 

 All the same, he points out that there is a greater resemblance 

 between the molluscan fauna of St. Helena and South 

 America than was recognised by previous observers. It is 

 especially a species resembling the exclusively Brazilian 

 genus Tomigerus that seemed to Mr. Smith to point to South 

 America as the likely source of some of the indigenous species. 

 He does not feel tempted to probe further into this mystery, 

 for he exclaims, " How they were transmitted is a hopeless 

 problem to solve, and although drift-wood, carried by oceanic 

 currents, is doubtless answerable for a good deal in the way 

 of distribution the subject must apparently ever remain one 

 of mere speculation." Nevertheless Dr. Kobelt f regards it as 

 highly probable that this molluscan fauna is the last remnant 

 of that of an ancient Mesozoic continent. 



About half of the species of the snails of St. Helena are 

 now extinct and occur only in a sub-fossil condition. Hyalinia 

 cellaria, H, alliaria and a few others, along with Amalia 

 (Milax) gagates are supposed to have been introduced with 

 plants. It is quite possible that some of them were brought 

 to St. Helena in that manner, still it is very remarkable that 

 the only slug thus conveyed should be one of our rarest 

 British species, and the one which has the widest range of all 

 slugs. It occurs in California, New Zealand, and other remote 

 localities, while none of our common Arions, Agriolimaces 

 or Limaces have found their way to the island. I am fully 

 convinced that Amalia gagates is one of the most ancient of 

 our European terrestrial species, as I explained in a previous 



* Pickard-Cambridge, O., " Spiders and Scorpions of St. Helena," p. 544. 

 f Kobelt, W., " Zoogeographische Stellung von St. Helena," p. 201. 



