150 TEST ACE A ATLANTIC A. 



Habitat Portum Sanctum, semifossilis ; exemplare unico in 

 arenis calcareis, a.d. 1849, a meipso, aliisque duobus a Barone 

 de Paiva, repertis. 



A single example of the common European H. lapicida was 

 taken by myself, during 1849, in a subfossil state, in Porto 

 Santo ; and two more have since been obtained by the Baron 

 Paiva from the Zimbral d'Areia in the same island ; so that we 

 have no option but to admit this northern form, no traces of 

 which have as yet been discovered in a recent condition, into 

 the extinct fauna of the archipelago. The examples before me 

 are genuinely subfossilized, and were found under precisely 

 similar circumstances as the various other species, and indeed 

 associated with them ; and we cannot doubt, therefore, that the 

 H. lapicida was at a remote period living in Porto Santo. 



Singular however as is the presence of this familiar European 

 Helix in the subfossil deposits of so isolated a locality, I am not 

 at all sure that there is any greater' anomaly about it than what 

 is indicated by the appearance (equally unintelligible) of the 

 well-known H. caperata, Mont., in a recent state, or of the 

 Balea perversa in the fissures of the basaltic rocks on the ex- 

 treme summit of the Pico de Facho, the highest mountain of 

 Porto Santo (where it was detected by myself during the same 

 year), and which, although it has since been retaken in the 

 identical spot and on an adjacent peak, has not been observed 

 elsewhere throughout the whole of these Atlantic Groups — 

 except at the Azores, where it is all but universal. Nor indeed 

 is it more extraordinary than the existence (if true) of the com- 

 mon European Patula rotundata, Miill., on the uninhabited 

 and nearly inaccessible rock, off the north-western coast, known 

 as the Ilheo da Fonte d'Areia. Such facts as these are of un- 

 usual geographical interest, to be accounted for if we are able 

 to do so, but absolutely unaltered if they cannot be made to 

 quadrate with any particular theories of our own. 



With evidence thus incontrovertible, I cannot but feel sur- 

 prised that Mr. Watson {Journ. de Conch. 229; 1876) should 

 think it necessary to call in question the right of the H. lapicida 

 to be quoted amongst the indigenous species of Porto Santo. 

 For, in the first place, he is scarcely accurate in asserting that 

 its sole claims rest upon a single individual which was found by 

 myself at the Zimbral d'Areia ; seeing that two more were ob- 

 tained subsequently, from the same locality, by the Baron Paiva, 

 and in a precisely similar state of subfossilization. These 

 specimens are now in my possession ; and I can see no more 

 reason for doubting the genuineness of the H. lapicida as 

 Porto-Santan than of any other Helix of which only three 

 examples might happen hitherto to have been met with. Con- 



