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) 

 „ „ Pfeif., Mon. Hel. iii. 39 (1853) 



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



(1872) 

 „ Pfeiff., 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 clamp 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 

 .ilient characters are in which the H. cuticula differs from the H. Webbiana. 



