120 TESTACEA ATLANTICA. 



to invalidate its specific claims,— for, after all, it is not more 

 surprising that the H. vulgata, which is so abundant in the 

 other islands of the Group, should be absent from Porto Santo 

 than that the //. punctulata, which occurs in the Porto Santo 

 and the Desertas, should be wanting in Madeira. No doubt the 

 H. nitidiuscula belongs to the same geographical type as the 

 vulgata ; but it also makes an evident approach towards the 

 H. depauperate, of the next section (Irus, Lowe), and, to me 

 at least, it seems altogether as rigidly defined, from a specific 

 point of view, as any Helix throughout the entire fauna. 



As compared with the very variable II. vulgata, the niti- 

 diuscula may be described as being considerably smaller and 

 rather more lenticular or depressed (its greatest diameter being 

 from 4 to 5 lines, instead of from about 5 to 7±, and the spire 

 being more obtuse, or less pointed, at the apex), and with its 

 surface not only appreciably more opake and free from the minute 

 setse which are generally more or less traceable in its ally, but 

 likewise very differently sculptured, — the entire shell, except 

 beneath, being closely beset with extremely diminutive, elon- 

 gated granules, which are just sufficiently removed from each 

 other to shape-out interspaces which have somewhat the appear- 

 ance of reticulations. 1 And there is also a peculiarity about the 

 aperture which will never fail to distinguish the if. nitidiuscula 

 from every state, or variety, of the vulgata, — namely the more 

 vertical prolongation of the axis into the columellary portion 

 of the peristome, giving a less rounded (or narrower and more 

 subquadrangular, or externally flattened) appearance to the 



whole. 



Although merging into each other by imperceptible grada- 

 tions, the H. nitidiuscula has in colour two extreme opposite 

 phases,— one of them white and bleached (though at times with 

 a faint flesh-coloured tinge), and quite destitute of markings, 

 having much the appearance at first sight of being subfossilized ; 

 and the other (which must be regarded as the normal one) of a 

 more or less dirty lurid yellow, but clouded on its upper side 

 with two (rarely three) extremely obscure brownish bands. This 



1 This was well defined by Mr. Lowe as ' confertim reticulato-granulata ; ' 

 yet Dr. Albers (whose eyesight must clearly have been at fault) professed 

 himself unable to see it !— 'cl. auctor,' says he, 'testam rninutissiine reticu- 

 lato-granulatam significat ; sub lente fortiori, tamen, nil nisi rudimenta 

 setularum, reque ac in form;! typica, observavi.' No wonder, after this, that 

 he should treat the II. nitidiuscula, as only a ' var. y ' of the vulgata; and 

 more particularly so, since he gives us no reason to suppose that he had even 

 so much as observed the absolutely invariable character of the mare vertical 

 direction of the columellary portion of the lower lip. With two such features 

 as these having escaped his notice, I am the more inclined to suspect that his 

 II. Hcuiintngi (in the diagnosis of which no mention is made of anything but 

 striae on tin surface) may be only the paler pha^i? of the //. nitidim&ula. 



