MADEIRAN GROUP. 247 



brilliant lustre being obviously connected with the perpetual 

 movement upon it of the mantle, and especially of its posterior 

 prolongation (a movement eminently characteristic, likewise, of 

 Nanina)' 



The precise species which were examined by Mr. Watson 

 are the melampoides, tornatellina, triticea, and oryza\ and, 

 through the kindness of Senhor J. M. Moniz, I have since been 

 enabled to forward to him living examples of what we have 

 hitherto regarded as the folliculus , Gron., but which Mr. Wat- 

 son (believing that the caudal gland could not possibly have 

 been overlooked in the widely distributed Gastropod which is 

 known on the continent by that name) has lately re-described 

 under the title of ' Lovea Wollastoni.' Into this particular 

 question I will not now enter (my own conviction, nevertheless, 

 being that the Madeiran and Mediterranean shells do not differ 

 specifically from each other, and that the important structure 

 upon which the genus Lovea is based has simply, in the case of 

 the folliculus, Gron., escaped the observation of European natu- 

 ralists) ; but, be the nomenclature what it may, there can at 

 any rate be no question that the subterminal gland is just as 

 conspicuous in the 'folliculus' (whether rightly or wrongly so 

 called) of Madeira as it is in the few species which were over- 

 hauled originally by Mr. Watson, and that consequently it is a 

 true and veritable exponent of his genus Lovea. As no less 

 than Jive of these immediately allied forms have therefore been 

 ascertained to possess the peculiarity to which attention has 

 just been drawn, we shall perhaps be warranted in assuming it 

 for the remainder, at all events until it has been actually 

 proved that it does not exist. 1 



Two species however which were examined by Mr. Watson 

 seemed to be destitute of the structure to which I have above 

 referred, and they must consequently be excluded from the 

 genus as denned by him. These are the common European 

 A. acicula and lubrica, enumerated above, which are mere 

 importations into Madeira, and belong apparently to a different 

 type. 



( Ferussacia, Bisso.) 



Lovea folliculus. 



Helix folliculus, Gronov., Zoophyl. fasc. 3. 296. t. 19. f. 15, 



16 (1781) 

 Achatina folliculus Pfeiff., Mon. HeL ii. 283 (1848) 



1 As for the Canarian species, they are too nearly related to the dis- 

 tinctively Madeiran ones, and to the folliculus, not to be admitted (by pre- 

 sumption) into the same genus ; but I would wish, nevertheless, to state that 

 their animals have yet to be examined. 



