MADEIRAN GROUP. 159 



various plants, especially the culms of Juncus maritimus ; and 

 although we found it in considerable profusion in that particular 

 spot, as well as along the commencement of the lofty precipitous 

 promontory immediately behind it, its area even there was 

 remarkably circumscribed, and I am not aware that it has sub- 

 sequently been met with in any other locality. The subfossilized 

 specimens of Porto Santo (which are extremely scarce, though 

 occurring at the Zimbral d'Areia) are a little smaller than these 

 living ones from the top of Pico Branco in the same island ; but 

 as they are nevertheless a trifle larger than the (equally subfos- 

 silized) Madeiran ones from Canical, we may perhaps adopt 

 Mr. Lowe's arrangement of them as, under the circumstances, 

 the most simple, namely ' a [normalis] fossilis, minor, sphaeru- 

 loidea, Maderce ; /3. fossilis, submajor, trochoidea, Portu 

 Sancto ; <y. recens, major, trochoidea, Portu SanctoS 



Apart from its rounded-conical outline, elevated (though 

 apically obtuse) spire, and somewhat flattened base, to which I 

 have already called attention, the H. sphcerula may be further 

 known by its very minute umbilical perforation, which is par- 

 tially closed over by the prominently expanded lamina of the 

 lower lip at its insertion into the axis, by its tumid but unkeeled 

 volutions and deeply impressed suture, by its narrow and some- 

 what horizontal aperture, which has a more or less evident 

 transverse callosity within it on the ventral wall, by the upper 

 and lower divisions of its peristome being widely separated but 

 joined by a corneous plate ; and by its surface (the lines of which 

 are rather light, though extremely irregular and subconfluent) 

 being beset with large granules which are unequal and indis- 

 tinct (occasionally evanescent) on the upper side, but coarse and 

 arranged as in a file below. Judging from the recent examples 

 now before me, from Porto Santo, the H. sphcerula is usually 

 white and without markings, though often with a very faint 

 lilac or plumbeous tinge, the whole shell, which is thick and 

 solid, having a colourless, bleached, china-like appearance. 



( Hystricella, Lowe.) 



Helix echinoderma, n. sp. 



T. trochiformis, subtus subplanulata perforata, undique 

 granulis magnis obtusis sat dense obsita ; spira elevata ; anfrac- 

 tibus convexis, subgibbosis, ultimo subtectiformi acute carinato 

 (carina simplici, solum antice gradatim obsolete subduplici) ; 

 umbilico punctiformi, aperto ; apertura subovali-rotundata, labris 

 continuis conjunctis, peristomate simplici, expanso, subrecurvo, 

 tenui, relevato. Long, axis 2^ tin. ; diam. 3^. 



Obs.- //. echinulatce, Lowe, valde amnis, sed multo major 



