66 TEST ACE A ATLAXTICA. 



well-nigh unrepresented in the conchy liferoiis deposits'), and 

 inasmuch as I have already mentioned that the truly aboriginal 

 ones may be estimated at about 138, it follows that so large a 

 proportion of the species which are strictly endemic have been 

 found subfossilized that there is strong presumptive evidence 

 for concluding that, sooner or later, the whole of them will be 

 detected in that condition. Indeed each year this is rendered 

 more and more probable, — every fresh examination of the beds 

 bringing to light some additional quondam-analogne (which 

 had hitherto escaped notice) of the living forms; whilst, on the 

 other hand, a critical research in new localities, and a still 

 closer one in those which were already known, is constantly 

 revealing the modern representative of some species which had 

 long been supposed to have passed wholly away.^ So that we 

 may fearlessly assert that continued and well-directed observa- 

 tions are tending rapidly to equcdize what were conceived to be 

 (so far as the aboriginal species are concerned) the 'recent' 

 and ' extinct ' faunas, and to show them, more and more, to be, 

 in point of fact, conterminous. 



It is quite clear however that many of tlie species which 

 were once excessively abundant, although they have not yet 

 completely ceased to exist, are at the present time of the 

 utmost rarity, — just lingering on, as it were, before they die 

 out. This is eminently the case with the Helix Lcnvei, Fer., 

 and the coronata, Desh., to which I have lately called atten- 

 tion, and which, although now extremely scarce, and confined 

 each of them, to a single spot of the most limited extent, are 

 nevertheless universal in the subfossiliferous beds of Porto 

 Santo, — the latter of them absolutely swarming. And on this 



' I say 'well-nigh,' because there are two or three exceptions to this 

 statement which will perhaps require to be ex]3lained, — such, for instance, 

 as the European Hyalina crystaUina, Miill., and the Patuhi injgm(Pa, Drap., 

 both of which are said to have been foimd by Mr. Watson in the beds near 

 Cani^al. Even instances, however, like these would seem merely to imply 

 that the species in question, although possessing (like the Helix hqncida, 

 Linn., subfossilized in Porto Santo) a wide European range, had nevertheless 

 siicceeded in colonizing this Atlantic region diu-ing the remote epoch when 

 the calcareous deposits were in process of fonuation. 



- In corroboration of this latter circumstance, I need only allude to the 

 discovery by Senhor J. M. Moniz, on the Ilheo de Cima, oif Porto Santo, of 

 the gigantic Helix Loivei, Fer., which for half-a-centmy had been assumed to 

 be totally extinct ; or to that, by myself, — on the extreme eastern peak of 

 Porto Santo, buried deep in the soil beneath slabs of basalt,— of the singular 

 little H. eoronata, Desh., which is so abundant in all the subfossiliferous 

 deposits of that island ; or to that, by Mr. Lowe and myself, of the H. tiarelJu, 

 W. et B., in the north of Madeira proper, — a sjiecies which swarms in the 

 beds near Cani^al, but which up to that date (namely the summer of 18.55) 

 had been looked upon as belonging exclusively (despite its enmi elation by 

 Webb in 1883, from examples which may or may not have been subfossilized) 

 to a former epoch. 



