TJIH CHIEF COLEOPTEROUS PAUNJ5. 



27 



from St. Helena to the Cape- Verde Islands, and embracing in its 

 course Ascension Island and the shoal ground on the equator. 



The next trace of a microtypal element in the southern Atlantic 

 is the island of Tristan d'Acunha ; and in obedience to the 

 natural train of thought, I shall begin with its flora, as I 

 have just left that of St. Helena. I should have liked to 

 have given in the Appendix a copy of the ' Flora St. Helenica,' 

 partly in illustration of what I have said regarding it, and 

 also for the purpose of contrasting it with a similar list of 

 the flora of Tristan d'Acunha given by Capt. Carmichael in 

 the 12th volume of the ' Transactions' of this Society ; for we 

 find the same elements in both, — a mixture of European and 

 African types in nearly the same proportion. The St.-Helena 

 list is rather long, and I hope may soon be supplied by a 

 better ; the Tristan d'Acunha list is short, and an abstract 

 of it may be convenient, and one is therefore given. The only 

 shrubby plants in the island (trees there are none) are JPhylica 

 arbor ea, and either one or two species of JEmpetrum. JPliylica is 

 an African genus represented by two species in St. Helena ; and 

 its occurrence in both St. Helena and Tristan d'Acunha fur- 

 nishes at least a presumption in favour of the two islands having 

 once been in communication with each other and with the 

 African continent. Empetrum (our Crowberry), on the other 

 hand, is, as every one knows, a most characteristic type of the 

 Scandinavian flora, and not less so of the Magellanic and Ant- 

 arctic Flora generally. So is the genus Chenopodium, wild spe- 

 cies of which also occur in both St. Helena and Tristan d'Acunha. 

 The genus Pelargonium has also species in both islands : it, not- 

 withstanding the presence of a straggler in Syria, is unquestion- 

 ably African, its species in that continent being numbered by hun- 

 dreds. It seems of no consequence that, as Dr. Hooker informs 

 me, the Tristan-d'Acunha species belongs to a different section 

 from the St.-Helena species. We should have expected that 

 they would be different ; the greater the deviation the longer 

 the probable period since they started from common parents, 

 and the stronger the presumption in favour of my view of the 

 connexion with Africa being very ancient. But what must 

 strike every one most in running their eye over Capt. Car- 

 michael' s list is the resemblance to our own flora. We there 

 see Ranunculus, jRumex, Cardamine,Atriplex, Gnaphalium, Apiim, 

 Carex, and similar genera. 



