182 TEST ACE A ATLANTICA. 



irregular transverse markings, though gi'adually and conspicuously 

 paler outside the aperture. 



So far as my own experience is concerned, the present modi- 

 fication of the H. polymorpha is peculiar to the Pico d'Anna 

 Ferreira (and its immediate vicinity), — a remarkably isolated 

 mountain of Porto Santo, to the south-west of the great central 

 mass ; and I may add that this is in exact accordance with the 

 equally repeated observations of Mr. Lowe, — who first met with 

 it, on the Pico d'Anna Ferreira, in 1828; yet the Baron Paiva 

 cites it from two other mountains, as well as from the Ilheo de 

 Ferro. I can only add, however, that, as the Baron's material 

 was not collected by himself, and was consequently subject at 

 times to great inaccuracies as regards habitat, I must be per- 

 mitted to look with some amount of suspicion upon these addi- 

 tional localities for the ' var. v. attrita.^ At any rate I have 

 myself paid considerable attention to the manner in which this 

 particular variety is (so to speak) concentrated on the Pico 

 d'Anna Ferreira, and have repeatedly observed that the exam- 

 ples which were obtained at a certain distance from the base 

 of the latter are gradually less and less pronounced in their 

 features, according to the length of the intervening area, until 

 they completely merge (as it has seemed to me) into the ordi- 

 nary 'X. discina,'' — the umbilicus especially (in such specimens) 

 being more or less intermediate between what obtains respectively 

 iu the two types (as normally defined). 



In a subfossil condition the ' v. attrita ' has been taken 

 sparingly, both by Mr. Lowe and myself, on the Campo de 

 Baixo (which well-nigh abuts upon the base of the Pico 

 d'Anna Ferreira) ; but, like every other modification of the 

 H. polymorpha which occurs at all except in a recent state, it 

 is extremely scarce. 



Helix tabellata. 



Helix tabellata, Lowe, Ann. Nat. Hist. ix. 116 (1852) 

 „ „ Pfeiff., Mai. Bldtt. 90 (1852) 



„ Id., Mon. Hel. iii. 164 (1853) 

 „ „ Lowe, Proc. Zool. Soc. Lond. 189 (1854) 



„ Alb., Mai. Mad. 28. t. 6. f. 19-21 (1854) 

 „ „ Paiva, Mon. Moll. Mad. 95 (1867) 



Habitat Maderam ; in coUibus aridis maritimis, prascipue 

 ad promontorium * Grarajao ' prope Fimchal, sub lapidibus gre- 

 garia. 



This is the smallest member of the Discula section which 

 has hitherto been found in the Madeiran archipelago, mea- 

 suring only about 3 lines across its broadest part ; for although 

 the most reduced examples of the 'var. povomphala^ of the 



