MADEIRAN GROUP. 145 



tulo-striata (striis hinc inde con fluent ibus, ad basin radiantibus), 

 fusco-cornea sed parce et irregulariter sublentiginoso-marmorata ; 

 anfr. 5^6 ssepius depressiusculus, ultimo antice subito deflexo et 

 constrictiusculo ; apertura valde depressa, angusta, lunata, callo 

 ventrali obsolete (interdum nullo) coarctato, columella brevis- 

 sima ; peristomate interrupto, albido, expanse, sed acuto, margi- 

 nibus lamina tenui junctis, basali versus insertionem late expanso 

 adpresso,intusleviter sub-biplicato (rarlus subsimplici),plicis sinu 

 plus minus distincto separatis. Long* may* 3 ; alt. 2 lin. 



Var. /3. bipartita. (semifossilis). Sensim minor, plica ex- 

 teriore dentiformi distinctiore, ab interiore (callum basalem ter- 

 minante) obsoletiore, sinu distincto separata. 



Helix obserata, Lowe, Ann. Nat. Hist, ix (1852) 

 Pfdff; Mon. Hd. iii. 169(1 853) 



Lowe, Proc. Zool. Soc. Lond* 182 (1854) 



Alb., Mai. Mad. 40. t. 10. f, 11-1 4 (1854) 



Paiva, Mon. Moll. Mad. 36 (1867) 



Habitat Maderam ; in intermediis, et borealibus et austra- 

 libus, parce occurrens* Juxta Canipal semifossilis, sed in statu 

 minore ( = ' var. /3 bipartita,' mihi), reperitur. 



The H. obserata is the most decidedly keeled of these imme- 

 diate species, as well as (proportionately) a trifle more flattened 

 above but more convex beneath ; and it is comparatively free 

 (often altogether so) from short hairs or bristles, but its surface is 

 more coarsely and distinctly ribbed. As in the H. fausta, its 

 perforation is completely closed over or sealed ; and the lower 

 margin of its peristome, although sometimes nearly simple, is 

 often distinctly thickened within into a corneous bi-sinuosity 

 (rather than a medial tooth-like plica), a structure which is 

 more particularly evident in the subfossil specimens from near 

 Canical, where this incrassabed inner process takes the form of two 

 tolerably conspicuous, though unequal, gibbosities (sometimes 

 the inner one preponderating) but more frequently the outer), 

 separated from each other by an excavation or sinus. This 

 latter phasis of the shell is rather smaller than the ordinary 

 recent one, and corresponds with the ' /&' of Mr. Lowe ; and 

 we may perhaps, therefore, further characterise it (as above) 

 as the ' var. /8. bipartita.' 



The present Helix is both local and rather scarce, though 

 occasionally far from uncommon at intermediate elevations in 

 Madeira proper, more particularly in the interior and towards 

 the south of the island. It has been taken by Mr. Leacock 

 in the Vasco Gril ravine, and towards the Great Curral ; though 

 the Baron Paiva reports it also from the vicinity of Sta. 

 Anna, in the north, from whence I have likewise examined a 



