200 HELIX. 



over minutely punctate ; whorls 5, convex, the inner smoother, 

 gradually, the outer more rapidly widening ; body-whorl depressed, 

 rounded at the periphery, flattened above, deeply deflexed anteriorly ; 

 aperture very oblique, perfectly oval ; peristome expanded, brownish, 

 continued as a heavy callus over the parietal wall, its basal portion 

 subreflexed, partially concealing the umbilicus. 

 Diam. 23-30, alt. 13-15 mill. 



Ins. Porto Sancto. 



H. LOWEI Ferussac, 1835. PL 52, fig. 90. 



Differs from the preceding (of which it may be a variety) in the 

 ,much larger size, the less obviously punctate surface, less oblique 

 aperture and narrower revolving bands, of which there are but two, 

 and these very slender. Diam. 45-55 mill. 



Porto Sancto. 



This largest of the Atlantic species is quite abundant in the quar- 

 ternary deposits of Porto Sancto, but according to Wollaston, only 

 a single specimen has been found alive. It seems to be replaced in 

 the living fauna by the very similar but much smaller If. porto*<uic- 

 tana. 



*** 



3. Lampadia Lowe. Imperforate ; vitrina-shaped, the whorls 

 thin, carinate, and very rapidly increasing ; aperture very large. 

 Mitra alb., preoc., is a synonym. 



H. WEBBIAXA Lowe, 1831. 'PL 51, figs. 55, 56. 



Imperforate, depressed, carinated, very thin, uniform olivaceous 

 brown, lighter below, with oblique irregular incremental stride and a 

 rather coarse granulation which is confined for the most part to the 

 central portion of the whorl, above and below the carina, and to the 

 neighborhood of the aperture, and which, although usually quite 

 obvious to the naked eye is frequently subobsolete ; whorls 3, very 

 rapidly widening, scarcely convex above, the last convex below, 

 bearing a compressed carina at the middle, and slightly descending 

 anteriorly ; aperture very oblique, oval, slightly angled at the place 

 of the carina ; peristome expanded, thin, its extremities not connect- 

 ed, columellar margin thin, entering, slightly reflexed and approv- 

 ed at the axis. Diam. 19, alt. 10 mill. 



Porto Sancto, Madeiras- 



Vitrina bocagei Paiva (pi. 51, figs. 57, 58) is a young shell of this 

 species. 



