234 TEST ACE A ATLANTIC A. 



cies is the subfossil one (at the Zimbral d'Areia) to which he 



alludes. 



Pupa calathiscus. 



Helix calathiscus, Lowe, Cambr. Phil. S. Trans, iv. 64. t. 6. 



f. 34 (1831) 



Pupa calathiscus, Pfeiff., Man. Eel. ii. 244 (1848) 

 „ „ Lowe, Proc. Zool. Soc. Loud. 212 (1824) 



„ „ Alb., Mai. Mad. 68. t. 16. f. 5, 6 (1854) 



„ „ Paiva, Mou. Moll. Mad. 134 (1867) 



Habitat Portum Sanctum ; ad cacumina montium in rupiuni 

 fissuris latitans. Semifossilis hinc inde haud infrequens. 



The comparatively large, and beautiful, P. calathiscus 

 (although belonging to the same solid, and strongly costate 3 

 geographical type as the P. monticola and corneocostata, which 

 are equally Porto-Santan) may be known from its allies not 

 only by its greater bulk and more oval form, but likewise by the 

 ribs of its extremely ventricose and appreciably banded volu- 

 tions being still coarser, as well as more curved and remote ; 

 and by its aperture having the lip a good deal developed and 

 often subpellucid, and the three palatial plaits subconfluent, — 

 the lower one being almost lost, or absorbed, in the general cal- 

 losity, whilst the middle one is elongated backwards into a 

 subtriangular process, and the upper one is appreciable but 

 short, being abruptly terminated internally, as well as 

 suffused into the (sometimes obsolete) lateral denticle. The 

 upper plait of the columella appears to be absent ; the inner 

 ventral one is small and immersed ; and the outer ventral 

 one is connected with the angle of the lip by a thick cor- 

 neous rim, which occasionally takes the shape (as in the Ma- 

 deiran P. laurinea) of a sub-isolated tubercle. 



The P. calathiscus, which is apparently peculiar to Porto 

 Santo, has much the same habits as the P. monticola (in its 

 normal state),— occurring more particularly on the ledges, and 

 within the crevices, of the rocks at a high elevation. Under 

 such circumstances it is tolerably common, amongst vegetable 

 detritus, on the summits of the Pico de Facho, the Pico 

 Branco, &c. ; but I have never observed it at a decidedly low 

 altitude. 



In a subfossil state the P. calathiscus is not generally 

 abundant ; nevertheless at the Zimbral d'Areia it was met 

 with by Mr. Lowe and myself in tolerable profusion. The 

 subfossil examples are a little smaller than the recent ones. 



