106 TESTACEA ATLANTICA. 



Helix erubescens, var. /3., Alb., Mai. Mad. 47. t. 12. f. 14- 



16(1854) 

 var. a. major, Paiva, I. c. 14 (1867) 



Habitat ins. omnes Maderenses (sc. Maderam, tres Desertas, 

 et Portum-Sanctum) ; in intermediis editioribusque degens. 

 In statu semifossili ad Canical Maderse, necnon in summo etiam 

 Desertse Austral is, reperitur. 



This is one of the most widely diffused, and variable, of the 

 Maderan Helices, it having been met with by Mr. Lowe, Mr. 

 Leacock, myself, and others on the whole five islands of the 

 archipelago (namely Madeira proper, the three Desertas, and 

 Porto Santo) ; and it is reported even from San Miguel, in the 

 Azores. Until within a comparatively recent period it was sup- 

 posed to be non-existent in Porto Santo (where its place seemed, 

 at first sight, to be supplied by the larger state (or ' /3. flue- 

 tuosa ') of the more keeled, and rather differently constructed, 

 semifossilized H. chrysomela); but in May of 1855 it was found 

 by myself, and subsequently by Mr. Lowe, on the ledges of the 

 damp rocks on the northern side of the extreme summit of the 

 Pico de Facho, in that island, from whence it has since been 

 obtained by the Baron Paiva. 



In a subfossil condition the H. erubescens is rather common 

 at Canical, in Madeira proper, and it was detected by Mr. Lowe 

 on also the extreme summit of the Southern Deserta (or Bugio) ; 

 but it has not been observed hitherto, so far as I am aware, in 

 any of the deposits (whether calcareous or muddy) in Porto 

 Santo. 



The H. erubescens passes through an almost infinite number 

 of changes, both in outline and hue, as regards the latter, 

 scarcely two specimens being precisely alike. Sometimes the 

 volutions are elegantly banded, at others some of the fasciae are 

 obsolete and at others the latter are more or less broken-up into 

 tessellated fragments ; while many individuals are unicolorous, 

 being entirely devoid of markings. The ground-colour (apart 

 from the darker bands) varies chiefly from a pale pinkish- 

 brown and whitish-yellow, into a dusky yellowish-grey ; and 

 there is generally (though by no means always) a more conspi- 

 cuous rosy tinge about the peristome ; and the surface is more 

 or less wrinkled, or malleated, as well as marked with oblique 

 irregular striae, which however are often extremely indistinct. 



But perhaps the principal aspects under which the H. eru- 

 bescens presents itself may be arranged, topographically, as 

 follows : 



a. porto-sancti, Woll. Rather less globose than the type, be- 

 ing a trifle more flattened both above and below, witli the aperture 

 a little more straightened or horizontal, and the basal volution 



