MADEIRAN GROUP. 131 



Helix maderensis. 



Helix maderensis Wood, Ind. Test. Sivpp. t. 8. f. 84 (1828) 

 „ „ Lowe, Camb. Fhii. S. Trans, iv. 48. t. 5. 



f. 22 (1831) 

 „ „ Pfe!f., Mon. Hel. i. 213 (1848) 



„ „ Loive, Proc. Zool. Soc. Load. 195 (18o4) 



„ „ Alb., Mai. Mad. 29. t. 7. f. 5-10 (1854) 



„ „ Paiva, Mon. Moll. 3Iad. 51 (1867) 



Habitat Maderam ; in aridis apricis submaritimis, a litore 

 maris usque ad 2000' s.m. copiose ascendens. 



The present Helix may be regarded as the central one, or 

 type, of the little group of forms of this immediate pattern, — 

 combining much the same sculpture as the tceniata, with the 

 smaller size, less depressed spire, and less carinated outline of 

 the compar. It is, however, distinctly, ^noo^e keeled than the 

 latter, and its sculpture (as already mentioned) is quite dif- 

 ferent, — its upper surface being merely crowded with closely- 

 set costate lines (instead of remote and elevated ridges), some 

 of which are rather larger and paler than the rest, with the 

 addition of a few coarse granules scattered sparingly towards 

 the aperture. Its umbilicus is relatively a trifie narrower than 

 that of either the cornpar or the tceniata. 



The mere variations of colour, in this and the two preceding- 

 species, are scarcely important enough to deserve notice, — the 

 single narrow band with which they are ornamented, both above 

 and below the keel, being occasionally (though not often) so 

 increased in width as to be comparatively conspicuous, whilst at 

 other times, on the contrary, it is nearly, or even altogether, 

 absent. Specimens in this latter condition, which are fre- 

 quently smaller and less developed than the average, would 

 seem to liave been mistaken by Albers (as is evident both from 



that even the former belongs to a distinctively Madeiran type, it is miich to 

 be regretted that he should not have rejected them in toto from his late 

 volume — as forms (to say the least) of uncertain habitat, and such as ought 

 never to have been introduced into the Catalogiie at all. Speaking of tlie 

 H. tainiata, he saj's : ' Cette esjD^ce n'a pas ete recueillie dans les Canaries, 

 mais a ete trouvee par M. Terver dans un ballot d'Orseille d'origine inconnue. 

 Sa forme rappelle tellement les esp^ces de Mad^re, qu'il est bien plus pro- 

 bable quelle appartienne reelement a ce second groupe d'iles, ou se recolte 

 egalement ce lichen.' And of the tiarella he adds : ' Cette esp^ce sc troure 

 rirante et svhfossile dans Madere, et il n'est guere probable, vu la difference 

 des deux fauues, qu'elle se retrouve dans les Canaries. Son origine en efl'et 

 est tout aussi douteux que celui de la tceniata, puisque, comme elle, la tiarella 

 ne s'est trouvee dans de I'Orseille de source inconnue.' And he then observes : 

 ' Ija patrie bien etablie de I'une de ces deux esp&ces donne la clef 2)our celle de 

 I'autre ;' so that, on Ms own shewing, as he acknowledged one of them to be 

 undoubtedly Madeiran, the other must have been Madeiran likewise. There- 

 fore why did he not eliminate them immediately ? instead of perpetuating, 

 b}^ not doing so, a geographical error. 



K 2 



