1878.] HEMIPTERA OF ST. HELENA. 451 



3. As regards the fauna and part of the flora— land connexion from 

 the north, and Europeau affinities. 



As regards the peculiar part of the flora — land connexion from the 

 south uniting Africa and America. 



4. As regards the marine Mollusca, diffusion by means of the 

 Agulhas current from the south. 



5. Affinities of the flora somewhat suggestive of extratropical 

 Southern Africa. 



Against the first of these theories (special creation) it may be 

 argued that such a method is contrary to, as far as we can judge, the 

 whole scheme of creation, and that, while many things can be urged 

 against it, there is nothing to support such a belief. 



Against the theories which necessitate the existence in time past 

 of a land communication with Africa or America, or both, all the 

 known facts militate. The non-existence in St. Helena of Amphibia 

 and terrestrial mammals 1 , the large number of peculiar species, as 

 well as the great depth of the surrounding sea, afford reasons for 

 thinking that it is extremely improbable that the island was ever 

 connected with either of these continents. 



The other theories will be alluded to in giving my own. 



A careful consideration of all the known facts leads me to believe 

 that two, if not three, epochs in the colonization of the island 

 may be distinguished, and that the great bulk of the inhabitants 

 came from the north, but not by means of a continuity of land. 



The first of these epochs, or that in which the earliest inhabitants 

 of St. Helena reached the island, occurred possibly early in the last 

 glacial period, but perhaps and (even probably) in Miocene times ; 

 and the reasons for thinking so, as well as for believing that the 

 colonists came from the north, I will now try to prove. 



In the first place, all the peculiar species belong either to peculiar 

 genera, or to genera which, if they have not yet been found in 

 Miocene formations, are (like the genera which have been found) so 

 widely distributed that it seems more than probable that they were 

 Miocene genera. The nearest relations of the peculiar genera are 

 also of this character. 



To begin with the terrestial fauna, viz. the Mollusca, the Coleo- 

 ptera, the Hemiptera, and the Arachnida. 



The molluscan genera are Succinea (with a peculiar subgenus), 

 Helix, Bulimus, and Achatina — genera which all date from the 

 Eocene, and which are all very widely distributed. 



The Coleoptera, being more numerous, are not so easily disposed 

 of. Taking Mr. Wollaston's estimate of what are aboriginal species, 

 we have 40 genera, of which 25 are peculiar. The remaining 15 

 genera include 10 actually known as Miocene, 4 of wide distribution 

 and therefore probably Miocene, and 1 which is only known from 

 Madeira in addition to St. Helena. Of the 25 peculiar genera, 21 

 at least belong to families or subfamilies which are Miocene, and 3 

 are allied to very widely-spread genera. 



The Hemiptera are not many in number, nor is our information 

 1 C. Darwin, ' Origin of Species,' 6th edition, p. 350. 



