222 TEST ACE A ATLANTIC A. 



The Pupa now under consideration, which has been ob- 

 served hitherto only in a subfossil state at Caniyal, was cited by 

 Mr. Lowe as the P. fusca ; but although its affinities are un- 

 questionably, to a certain extent, with that species, I feel satis- 

 fied that the two are not specifically identical, for not only is 

 the P. Wollastoni considerably smaller than (and perhaps not 

 quite so coarsely and thickly striated, at any rate posteriorly, as) 

 the fusca, but it entirely wants the tumid volutions which are 

 so eminently characteristic of that species ; and the lateral den- 

 ticle of its lip is less developed or internally prominent. Added 

 to which, the number of its whorls appears generally (as it seems 

 to me) to be one less. 



But, in point of fact, the P. Wollastoni seems to be far 

 nearer, unless indeed I am much mistaken, to what I would 

 regard as the typical state (namely the ' fi. arborea ') of the P. 

 sphinctostoma, of which it might almost be looked upon as a 

 small, or depauperated, race. Nevertheless it differs from the 

 latter in its comparatively diminutive size, and somewhat ob- 

 tuser apex ; in its body-volution being nearly free from any 

 indications of sculpture, whilst the succeeding ones are, on the 

 contrary, more coarsely striate ; and in its lateral denticle being 

 less developed. 



Pupa sphinctostoma, 



Helix sphinctostoma, Lowe, Cambr. Phil. S. Trans, iv. 63 



(1831) 



Pupa sphinctostoma, Pfeiff., Mon. Hel. ii. 335 (1848) 

 Lowe, Proc. Zool. Soc. Lond. 209 



(1854) 

 Alb., Mai. Mad. 64. t. 15. f. 29-30 



(1854) 

 Paiva, Mon. Moll. Mad. 124 (1867) 



Habitat Maderarn ; vel (var. a. rupestris) sub foliis emor- 

 tuis Sempervivi tabulceformis, Haw., in rupibus maritimis cre- 

 scentis, vel (var. /3. arborea) inter muscos atque sub cortice 

 laxo in truncis Laurorum, latens. 



The P. sphinctostoma is perhaps the most difficult and in- 

 constant of all the Maderan Pupce, and yet certainly it is one 

 of the most truly indigenous ones, occurring in various situa- 

 tions, and at diverse altitudes, throughout Madeira proper, to 

 which island it seems to be peculiar. In a general sense it may 

 be said to assume two opposite phases, which might well be re- 

 garded as specifically distinct did they not pass into each other 

 by almost imperceptible gradations. In the former of these 

 (the ' var. a. rupestrisj Lowe) the outline is less parallel, or 

 more attenuated towards the apex, the consistency is much 



