irSITANIAN" EEGION. 



93 



to the section Helico-limax, tlie Cyclostomas to the sub-genus 

 Craspedopoma, and half the Pupas to Vertigo. 



1 Bulimus 2 Cionella 3 Limnaea 1 



Arion 



Limax 4 Glandina 4 Pupa 23 Ancylus 1 



Testacella 2 Azeca 3 Balea 1 Conovulus 3 



Vitrina 3 Tornatellina 1 Clausilia 3 Pedipes (afra.) ... I 



Helix 76 Zua 2 Cyclostoma 2 



Of the 92 found in Madeira or the Dezertas, 70 are peculiar ; 

 54, of which 39 are peculiar, inhabit Porto Santo and its islets ; 

 1 1 others, of which 4 are widely diffused, are common to Madeira 

 and Porto Santo. One species is peculiar to the Dezerta Grande ; 

 1 species and 1 variety to the southern Dezerta (Bugio) ; 1 to 

 the northern (Cho) ; 1 variety to Ferro. Seven species are 

 common to the Dezertas ; 1 to the great and northern Dezertas ; 

 5 to Madeira and Dezerta Grande; and 3 to Madeira, Porto 

 Santo, and the Dezertas. Of those species which inhabit more 

 than one island, the specimens from each locality are recog- 

 nisable as distinct races or geographichal varieties. Helix sub- 

 plicata and papilio are found on the Ilheo Baxo ; H. turricula on 

 Cima. Of the total number (134) 112 species are peculiar to the 

 Madeira group; 5 are common to the Canaries; 4 to the Azores, 

 and one to the Guinea coast; 11 are common to Southern Europe, 

 besides 2 LimiKBids and 7 slugs, which may have been recently 

 introduced, viz. : — 



Arion empiriconim. 

 Limax variegatus. 



„ antiquorum. 



„ agrestis. 



„ gagates. 

 Testacella Maugei. 

 „ haliotidea. 



Helix cellaria. 



„ crystallina. 



„ pisana. 



„ pulchella. 



„ lenticula. 

 ( „ lapicida, fossil). 

 Cionella acicula. 



Zua lubrica, var. 



„ follic^^lus. 

 Bulimus decoUatus. 



„ ventrosus, Fer. 

 Balea perversa (p. 293). 

 Limnsea truncatula. 

 Ancylus fluviatilis. 



Great quantities of dead shells of the land-snails are found in 

 ancient sand-dunes near Canigal, at the eastern extremity of 

 Madeira, and in Porto Santo, including 64 of the living species 

 and 13 which have not been, found alive. As the fossil examples 

 of several species are larger than their living descendants, it 

 is possible that some of those reputed to be extinct have ■ only 

 degenerated. It is a remarkable fact that some of the com- 

 monest living species are not found fossil, whilst others, now 

 extremely scarce, occur abundantly as fossils.* 



* Helix tiarella, W. and B., was supposed to be extinct, but in 1855 Mr. Wollaston 

 detected it alive in two almost inaccessible spots on the north coast of Madeira : it is 

 not a native of the Canaries. 



