90 TEST ACE A ATLANTIC A. 



districts) in Madeira. I have not myself observed it in any of 

 the other islands of the group, but it is recorded by the Baron 

 Paiva as existing sparingly on the Southern Deserta or Bugio ; 

 though I cannot but suspect that this latter habitat must be 

 regarded as still requiring corroboration. 



(§ Campylwa, Beck.) 



Helix Lowei. 



Helix portosanctana, ^. gigantea, Loive^ Cambr. Phil. S. 



Trails, iv. 46. t. 5. f. 16 (1831) 

 „ Lowei, Fer., Bull, de Zoolog. 89 (1835) 

 „ „ Pfeif., Mon. Hd. iii. 233 (1835) 

 „ „ Loive, Proc. Zool. Soc. Lond. 169 (1854) 

 „ „ Alb., Mai. Mad. 82. t. 17. f. 11, 12 (1854) 

 „ „ Paiva, Mon. Moll. Mad. (1867) 



Habitat Portum Sanctum ; in statu semifossili vulgaris. 

 Etiam recens cl. J. M. Moniz, sub lapide magno (quasi sepulta), 

 in ins. parva ' Ilheo de Cima ' dicta, semel detexit. 



The H. Lowei (the larger examples of which measure up- 

 wards of two inches across the broadest part) stands pre-eminent 

 amongst the Madeiran Helices for its gigantic stature ; but it 

 has been a question, with various monographers, whether it 

 should be regarded as anything more, in reality, than the 

 quondam, highly-developed state of the present H. portosanc- 

 tana — which in nearly all respects except size it closely re- 

 sembles. Without entering into this problem, which is perhaps 

 unsolvable, I will merely add that it has more often been looked 

 upon latterly as specifically distinct ; a supposition which is ren- 

 dered none the less probable from its having been lately ascer- 

 tained not to belong altogether to a fauna that has passed 

 away, — a single living example, which was found by Senhor J. 

 M. Moniz beneath a large stone (and at a considerable depth 

 underground) on the little island known as the Ilheo de Cima, 

 proving to a demonstration that the species, in an unaltered 

 condition, still lingers on, and that too in company with its 

 modern analogue the H. portosanctana. 



But considering how abundant the H. Loivei is in the sub- 

 fossiliferous beds of Porto Santo, there can be little doubt that 

 the species (which is now practically all but extinct) was once 

 dominant ; whilst the comparative rarity of the H. portosanc- 

 tana in a semifossilized condition would seem as if the former 

 had in some measure been supplanted by the latter (which at 

 present is so universal). Still, I do not think that we have suf- 

 ficient evidence for assuming that the one has been, by any 

 fancied process, altered into the other, — for intermediate links do 



