MADEIRAN GROUP. 107 



just appreciably keeled. The sm-face is less malleated than in 

 the other varieties, but tlie minute strias are somewhat more 

 regular and apparent. Although very variable in hue, this is 

 usually a highly decorated state, the ground-colour being often 

 of a comparatively clear yellow. Detected by myself and Mr. 

 Lowe on the northern side of the extreme summit of the Pico de 

 Facho, in Porto Santo. 



j3. [norinalis]. — This is the phasis which obtains throughout 

 the intermediate and lofty elevations of Madeira proper, and on 

 the Deserta Grrande ; and it is rather less flattened (or more in- 

 flated) than the Porto-Santan one, with the aperture less 

 straightened, and the surface more appreciably malleated, but 

 somewhat less evidently striate. It is often extremely thin and 

 semi-transparent ; and its colour is so inconsistent that it may 

 be said to pass through almost every gradation (in that respect) 

 to which the species is liable. Even its contour is by no means 

 fixed, some examples having the spire more raised than others ; 

 and, on the whole, the specimens from the Great Deserta may 

 perhaps be said to be a trifle larger and more globose, as well as 

 more highly decorated, than those from Madeira proper. 



7. advenoides, Paiva. — A rather larger (on the average) but 

 less globose form, which is characteristic of the Northern De- 

 serta (or Ilheo Chao), but wliich likewise makes its appearance 

 in the extreme east of Madeira proper, — namely on the Sao Lou- 

 renfo promontory, which stretches out in the direction of that 

 small and flattened island. It was inadvertently regarded by Mr. 

 Lowe as identical with the H. advena, W. et B., — a species 

 wrongly stated to be Canarian, but which however appears 

 equally to be not Madeiran (it being peculiar to the Cape Verde 

 Group).^ The ' 7. advenoides ' is not merely a little larger 

 than the type, but relatively a trifle more depressed ; its surface 

 is a good deal roughened and malleated ; its substance is per- 

 haps rather more solid ; and its colour is of a more or less pale, 

 but dull, yellowish-brown, with the bands for the most part con- 

 siderably broken-up and interrupted, — giving a slightly tessel- 

 lated appearance to the whole. There is seldom anything of a 

 rosy tinge about this variety, not even around the peristome 

 (which is nearly always white). 



8. hycena, Lowe. — The largest of all the phases of the H. 

 eruhescens, — some of the examples attaining a comparatively 

 gigantic stature (being ten lines across the widest part, and six 



> The H. advena, W. et B., is a more shining and nmnalleated shell, but 

 with the transverse striaj nevertheless much more distinctly and regularly- 

 developed ; its apex is a little more obtuse, its apertixre is a trifle more roimded 

 (there being no tendency to a keel), and its upper lip is not so much deflexed. 

 Its plan of coloration too, which involves often a faint j^^ianheous (or leaden) 

 tinge, is dilferent. 



