HELIX. L )(ll 



H. MKMBRAXACKA LoWC, 1852. PI. 51, figs. 4-"), 4<i. 



Imperforate, depressed globose, excessively thin, flexible, pellueid, 

 yellowish or greenish corneous, usually more or less variegated with 

 opaque whitish Hecks and reticulations, which Hinu-tini.-s form a 

 stripe at the central keel ; whorls 4, rapidly increa.-in- ; spin- low, 

 obtuse; body-whorl acutely cariuated at the middle. th<- carina In- 

 coming obsolete toward the aperture ; not deflected anteriorly : apcr- 

 ture large, broad oval lunar, oblique; peristome simple, thin, ends 

 scarcely converging; columella simple, arcuate. 



Diam. 10, alt. 6 mill. 



Madeira. 



The excessively thin, easily indented substance of thi> specie- will 

 distinguish it from any of its allies. The last whorl is not so acutr- 

 ly carinated as in H. webbi>i. 



H. CUTICULA Shuttleworth. PI. r,i , figs. 47-41). 



Jmperforate, depressed-conic, very thin and fragile, with a silky 

 lustre, light green, costulate-striate; spire low, conic, apex prom- 

 inent; suture impressed; whorls .*>, rapidly increasing, convex below 

 the sutures and on base, but concave above and below the prominent 

 peripheral carina; body-whorl large, depressed, carinattd to the 

 aperture, not deflected anteriorly, indented at the axis; apertun- 

 transversely oval, angulate at position of carina ; peri-tome acntr. 

 membranous; columella deeply, vertically entering. 



Diam. 7, alt. 4] mill. 



Teneri/e and Palm. C<ni< 



Section VIII. IHKKUS Moiittbrt, 1810. 



Helices of the section Ibern* are very numerous both in species 

 and individuals in central and southern Italy, and in Sicily: and 

 curiously enough, there have been a few trans-Mediterranean spe- 

 cies discovered in recent years. There is great lattitude of opinion 

 concerning the synonymy of the group, arising from the fact that 

 transition forms between many of the "species" render any hard- 

 and-fast lines of demarkation between them wholly arbitrary ; an. I 

 the subject lias been still further complicated by a number of di tig- 

 noses of "new species," without figures, each of which admits of be- 

 ing applied to several forms. 



The Sicilian species form a perfect series of gradation- between 

 the carinate flattened forms and the globose elevated ones. They 



