158 TEST ACE A ATLANTIC A. 



noticed had it not been a local one, and neither of which are 

 very decidedly aberrant), I can see no advantage in creating 

 confusion by registering a number of varieties and ' subvarie- 

 ties ' (so-called ) which are scarcely distinguishable from each 

 other, and which have been made to depend on the greater or 

 less elevation of the axis, and the greater or less development 

 of the granulations. I will just mentior, however, that the 

 Madeiran examples (from Porto Moniz) have their spire just 

 appreciably more raised than even the most conical ones from 

 Porto Santo. 



Helix sphaerula. 



Helix subcallifera, Lowe, ollm, in liU. 

 „ sphaerula, Id., Ann. Nat. Hist. ix. (1852) 

 „ „ Id., Proc. Zool. SoG. Load. 185 (1854) 



„ „ Alb., Mai. Mad. 82. t. 17. f. 8-10 (1854) 



„ „ Paiva, Mon. Mol. Mad. 43 (1867) 



Habitat Maderam (seniifossilis), et Portum Sanctum (semi- 

 fossilis ac recens) ; rarissima. 



Although the smaller and ratlier more globose pbasis (which 

 is found only in a subfossil condition, and only in the Canipal 

 beds of Madeira proper) of this species has rather the 'prima 

 facie appearance of the H. compacta type, yet it will be seen on 

 inspection to be in reality very different, — the larger one, which 

 occurs in a living state on the mountains of Porto Santo, so far 

 explaining the other (which is not only ' smaller ' but, from its 

 decomposed surface, practically more obscure) as to render it 

 evident that the H. sphcerida makes a most decided approach 

 in the direction of the H. cheiranthicola. This is particularly 

 observable, not only in its obtusely conical outline, elevated 

 spire, and rather flattened base, but likewise in the construction 

 of its aperture and peristome, and even (when the specimens 

 are not simply white, as is generally the case) in its law of 

 colouring, — there being often faint traces of an obsolete fascia 

 encircling the umbilical area, which is never indicated in the 

 true and undoubted members of the section Caseolus. 



Mr. Lowe having first enunciated this Helix from the 

 Canifal form of it (which, as just mentioned, is smaller, rounder, 

 and exclusively subfossilized), we have no option but to treat 

 that particular state as the normal one. Nevertlieless in speak- 

 ing of its characters we must needs do so from the Porto-San- 

 tan recent (larger) type, because the distinctive features of the 

 shell are alone readily appreciable in fresh and living examples. 

 It was during our visit to Porto Santo in jMay of 1855 that the 

 H. sphcerida was taken by Mr. Lowe and myself on the extreme 

 summit of the Pico Branco, — adhering to tlie upper parts of 



