188 TEST ACE A ATLANTIC A. 



Helix Bulwerii, Pfeiff., Mon. Hel. iii. 161 (1853) 

 Bulveriana, Lowe, Proc. Zool. Soc. Lond. 192 (1854) 

 Bulwerii, Alb., Mai. Mad. 24. t. 4. f. 12-15 (1854) 

 Bulweriana (pars), Paiva, Mon. Moll. Mad. 94 (1867 ) 

 rota, Lowe, olim, in litt. 



Habitat Portum Sanctum; in montibus una cum specie 

 prsecedenti degens. Semifossilis parcissime collegi. 



As already mentioned, the H. Bulwerii is essentially a 

 Porto- Santan species, occurring on the mountain-slopes of a 

 rather high elevation, often in company with the H. Albersii. 

 In a subfossil condition it is extremely scarce, though I have 

 taken it out of the sandy, or muddy, deposit of a sea-cliff below 

 the Pico dos Maparicos, to the westward of the Villa. 



The H. Bulwerii (the specific title of which appears to have 

 fc^en unwarrantably altered by Mr. Lowe, in 1831, into ' Bul- 

 veriana''} is, on the average, a trifle larger than the H. Albersii; 

 and it is also a little less solid in substance, and of a darker 

 hue, it being browner, or more castaneous, both above and 

 below, though the whorls have their single medial band obsolete, 

 and the ultimate one (which is more strongly and acutely cari- 

 nated, and not deflected in front) is free from the pale ochreous 

 tinge, or dilution, behind the aperture. Its spire is more 

 rounded and obtuse at the apex, or dome-shaped, the volutions 

 being even still flatter and in a more continuous curve, an 

 arrangement which causes the keel to be more downwardly 

 inclined, and more tectiform or produced. Its entire surface 

 is a little more densely and evidently granulated ; its base is 

 somewhat flatter, with the umbilicus just perceptibly deeper 

 and more cylindrical ; and its aperture, which is more angulated 

 in the middle, has the upper margin of the peristome straighter, 

 or less inwardly curved. 



Like the H. rotula, and indeed like so many of the Helices, 

 particularly in Porto Santo, the H. Bulwerii has an occasional 

 somewhat greenish-white, almost colourless, albino state ; but 

 as the same tendency to decoloration exists in so large a number 

 of the species, I can scarcely regard that peculiar (and, as it 

 were, accidental) condition as representing a distinct ' variety,' 

 - properly so called. 



Helix tectiformis. 



Helix tectiformis, Sow,, Zool. Journ. i. 57. t, 3. f. 6 (1824) 

 Lowe, Cambr. Phil. S. Trans, iv. 45, t. 5. 



f. 12 (1831) 



Pfeiff., Mon. Hel. i. 208 (1848) 



Lowe, Proc. Zool. Soc. Lond. 192 (1854) 



Alb., Mai. Mad. 22. t. 4. f. 4-6 (154) 



