114 TESTACEA ATLANTICA. 



laneous, but unquestionably veritable, Porto-Santan shells 

 which were obtained by the Baron Paiva ; and I have no hesi- 

 tation, therefore, in admitting the species into the Madeiran 

 catalogue. 



Important however as is the addition of the H. caperata to 

 the fauna of the Atlantic islands, it suggests a far more inte- 

 resting enquiry as to whether the unique H. lauta, Lowe, 

 which has baffled all subsequent observations for nearly fifty 

 years (and which Mr. Lowe, in his last enumeration of the 

 Madeiran Land-Mollusca, in 1854, struck out of the list as 

 having been introduced on insufficient evidence), may not prove 

 to be, after all, but a largely developed phasis of this variable 

 European Helix. The original type, which is now before me, 

 and which was given to Mr. Lowe by the late Gr. B. Sowerby as 

 having been found in Porto Santo by Mr. Bulwer, differs in 

 scarcely any respect (so far as I can perceive) from these 

 two examples (likewise Porto-Santan) of the H. caperata, 

 except that it is a little larger and rather more globose, the 

 ultimate volution being rounder, or more inflated and obtuse 

 (having no tendency whatever to be keeled), and therefore 

 more broadly developed. This peculiarity of its basal whorl 

 seems to me to be the only feature which could by any possi- 

 bility be laid hold of to separate the H. lauta ; for the shell is 

 not at all larger than occasional specimens of the caperata 

 from more northern localities [indeed it is not so large as the 

 more coarsely and less evenly striated race, with a slightly 

 wider umbilicus, which is abundant around Mogador, on the 

 opposite coast of Morocco, and which was enunciated by Mr. 

 Lowe as the 'caperata, var. /3. mogadorensis '], whilst its 

 sculpture is absolutely identical with that of the latter, and its 

 umbilicus (though certainly a trifle more cov^red-in) is but 

 very slightly ' smaller,' its ' pallid hue ' being probably the 

 mere result of Mr. Bulwer's unique example having been found 

 dead, bleached, and decolor ated (not ' decorticated ') on the dry 

 calcareous plains of Porto Santo. 



Whether however this somewhat greater tumidity of the 

 ultimate volution, and the just appreciably diminished umbi- 

 licus, of the H. lauta are of sufficient importance to separate it 

 from the H. caperata, may still perhaps be open for considera- 

 tion ; though rny own belief is, that the species can scarcely be 

 regarded as having been founded upon more, in reality, than a 

 mere accidentally globose individual of the latter, a suppo- 

 sition which is rendered all the more probable, now that the 

 caperata in its normal condition has unexpectedly been brought 

 to light in the very island in which Mr. Bulwer was said to 

 have obtained the actual type on which the //. lauta was esta- 



