CANARIAN GROUP. 335 



(instead of obliquely plicate) surface it makes a certain approach 

 towards the (otherwise altogether dissimilar) H. Webbiana, 

 Lowe, of Porto Santo. 



Apart from its flattened form and powerful keel, the H. 

 Berkeley i may be further recognized by its entire surface (which 

 is opake and of a pale-brown) being asperated with large and 

 irregular tubercles, which on the upper side diminish in bulk 

 towards the nucleus, and which on the under are file-like, par- 

 tially transverse, and very densely crowded together. Its lower 

 part is comparatively convex ; its keel is somewhat compressed 

 above (through the adjoining portion being slightly worn-out, 

 or concave) ; its volutions are very obsoletely bifasciated ; and 

 its peristome (the upper and lower lips of which are not joined 

 by a corneous plate across the basal whorl) is very broad, white, 

 and reflexed. 



The H. Berkeleyi was detected by Mr. Lowe and myself, on 

 the 12th of April 1858, on a dry calcareous slope (close to the 

 sea), between Maspalomas and Juan Grande, in the south-east 

 of Grand Canary; where we likewise met with it (and some- 

 what less sparingly) in a subfossil condition. 



( Mitra, Albers.) 



Helix cuticula. 



Helix cuticula, Shuttl, Bern. Mitth. 142 (1852) 

 Pfeiff., Mon. Hel. iii. 39 (1853) 



Mouss., Faun. Mai. des Can. 69. pi. 4. f. 4-6 



(1872) 

 Pfei/., Mon. Hel. vii. 74 (1876) 



Habitat Teneriffam, Gomeram, et Palmam; in sylvaticis 

 humidis editioribus, rarior. 



This singular, Vitrina-like little Helix may be known by 

 the paucity of its (obliquely and densely, but delicately, striated) 

 whorls, by its extremely thin, pellucid, pale-green (but not very 

 shining) substance, by its relatively rather large aperture (the 

 peristome of which is acute, and not at all recurved), and by its 

 compressed, sharply developed keel, which is visible also in 

 the volutions of the spire, where it closely adjoins the suture, 

 and occasionally well-nigh overhangs it. 



The H. cuticula, which may be regarded as the Canarian 

 representative of the (nevertheless comparatively gigantic) H. 

 Webbiana, 1 Lowe, of the Madeiran Group, appears to be scarce, 

 and confined to damp sylvan spots of a rather high altitude, 

 in which situations it has been met with in Teneriffe, Gomera, 



1 I have already pointed out, at p. 102 of this volume, what the most 

 salient characters are in which the If. cuticula differs from the If. Webbiana. 



