322 Mr. F. O. P. Cambridge on 



the breakin.2^-up o£ the genera and species in question into two 

 or more. I3ut what precise extension is given to the terms 

 genera and species is purely a matter of taste ; the actual 

 facts are in no way affected. Further, whether we have to 

 do with actual or assumed continuity in time and space, 

 the warrant for the conception of species disappears : for 

 historical-geographical considerations it is too contradictory ; 

 the ideas of species as something separating, and of develop- 

 ment in time and space, arc incommensurable. Thirdly, for 

 the purpose of our present study it does not matter at all 

 whether the representatives are regarded as identical species, 

 or as different forms of the same species, or as nearly related 

 species. The point is in the evidence of close relationship, 

 and it does not matter much what systematic expression we 

 give to this fact. 



Conclusion. 



We have now reached the end of our study. We have seen 

 that the faunas of higlier latitudes represent the coeval relics 

 of the almost uniforml}' developed and almost universally 

 distributed Early Tertiary faunas, as they have been evolved 

 under the influence of the cooling of the climate, by a process of 

 separating out and selection. The similarity of the operating 

 causes secured that the same components of the old fauna 

 remained behind in both north and south ; and thus has 

 arisen the great and still well-marked similarity of the two 

 faunas. 



XLI. — On a Collection of Spiders from the Bahama Islands 

 made hy J. L. Bonhote, Esq. / with Characters of a neio 

 Genus and Species of Mygalomorphse. By F. O. FiCKARD 

 Cambridge, B.A. 



[Plate VII.] 



A SMALL but valuable collection of Arachnida was made in 

 the neighbourhood of Nassau by Mr. Bonhote and presented 

 to the British Museum. Amongst other interesting forms 

 were two adult males of the family Theraphosida^, large hairy 

 spiders locally termed Tarantulas. For these a new genus 

 has been made, and the species is also new : it is characterized 

 by the presence of stridulating-spines on the trochanters of 

 the first pair of legs and the palpus. 



