2 WATSON : RELATION OF MADEIRAN MOLLUSCA TO OTHERS. 



two Other species which, though passed by Mr. Wollaston, ought, 

 I am persuaded, to be excluded. One is Helix lapicida — a species 

 represented by one soUtary dead shell ; the second H. caperata, 

 of which also only one well-authenticated specimen — and it too 

 a dead shell — has been found, no faith being possible in the 

 two additional specimens supplied with other incredible dis- 

 coveries to the Baron de Paiva by one of his over-zealous 

 collectors. The addition of these two brings up Mr. WoUaston's 

 reduction to thirty, the deduction of which from two hundred 

 and six leaves one hundred and seventy-six as the number of 

 Madeiran species with which we have seriously to deal. Among 

 the thirty species thus excluded, I have purposely left Pisidhwi 

 ivatsoni Paiva. I found it in considerable numbers and gave 

 specimens of it to the Baron de Paiva, who published it 

 without my permission. It has never been carefully examined, 

 and Mr. Wollaston did well to ignore it, though, as in Madeira 

 the solitary representative of its whole class, it is full of interest. 



Of the one hundred and seventy-six above-mentioned as 

 true inhabitants of Madeira, nine species are semi-marine. These 

 are Pedipes afra Gmel., Melampus exiguus I.owe, Auricula 

 cpqualis Lowe, A. watsoni WoU., A. gracilis Lowe, Alexia pai- 

 vana Pfr. (Selvagens), Truncatella truncatula Drap., T. lowei 

 Shuttl., Assiminea litorea d. Chiaje ; these though air breathers 

 are really sea-dwellers, and in any question of distribution must 

 go with the Marine rather than with the Terrestrial species. 

 Deducting then these nine from the one hundred and seventy- 

 six there remain one hundred and sixty-seven Terrestrial species, 

 and of these only thirty-four species are found anywhere else 

 than in this little group of islands. I say thirty-four, not thirty- 

 five, because the solitary specimen of a fresh but empty shell 

 of Lovea tornatellina Lowe which I found in Grand Canary 

 does not entitle it to rank as a Canarian species. 



Thirtj'-four then of the Madeiran species are all which this 

 group of islands has in common with the rest of the world. 

 The overlap is very small, but even this must be reduced. 



J.C, vii, Jan,, 1892. 



