MADEIRAN GROUP. 139 



appearance. Its peristome, although narrowly interrupted, is 

 greatly expanded and recurved. 



In its mode of life, too, the H. stellaris is altogether dif- 

 ferent from the lentiginosa ; for whilst the latter occurs almost 

 exclusively (as indeed I have already mentioned) under the 

 plants of Sevnpervivum which stud the faces of the rocks, both 

 along the abrupt sea-cliffs and in the ravines of an intermediate 

 elevation, the stellaris, on the other hand, resides beneath stones, 

 like the H. arcta, in dry and exposed places only slightly 

 removed above the level of the sea, where moreover it has the 

 curious habit of coating itself over with a covering of hardened 

 mud. Even Dr. Albers was not able to ignore in toto this 

 essential difference in their habitats, adding : ' Formse duae 

 non promiscue degunt ; major enim [i.e. the H. lentiginosa] 

 ab oppido Funchal versus orientem, ad promontorium Cabo 

 Garajao dictum, occurrit ; varietas pusilla autem [i.e. the 

 H. stellaris'] in cacumine tantum promontorii supra Praia 

 Formosa, ab oppido Funchal versus occidentem, collegitur 

 (1. c. p. 39). He might however have made the case very much 

 stronger. 



The H. stellaris was first detected by myself, during April 

 1848, beneath stones, at the east end of the cliff, or basaltic 

 ledge, overlooking the Praia Bay, about three miles to the west- 

 ward of Funchal, a locality in which it was shortly afterwards 

 (namely on the 1st of May of the same year) taken by Mr. 

 Leacock. The Baron Paiva records it from other places within 

 the P^unchal district, such as the Pico da Cruz, the Feijaa dos 

 Asnos, the Kibeira de Sta. Luzia, and the Ribeira de Vasco Gil. 



Helix arcta, 



Helix arcta, Lowe, Cambr. Phil. S. Trans, iv. 42. t. 5. f. 7. 



(183.) 



Pfei/., Mon. Hel. i. 404 (1848) 

 Lowe, Proc. Zool. Soc. Lond. 180 (1854) 

 Alb., Mai. Mad. 40. t. 10. f. 5-10 (1854) 

 Paiva, Mon. Moll. Mad. 33 (1867) 



Habitat Maderam, et ( sec. Paiva) Desertam Australem ; in 

 collibus aridis maritimis subinferioribus hinc inde copiose con- 

 gregans. 



The H. arcta is one of the smallest of the Madeiran Helices 

 (the larger examples measuring only about a line and a half 

 across the broadest part) ; and it is one which is more par- 

 ticularly gregarious in dry submaritime places of a rather low 

 altitude. It abounds on the Cabo Grarajao (or Brazen Head), 

 as well as towards Canico and Sta. Cruz, and (in the west of 



