PLATE CXXXIII. 



In conformity with our annunciation in the last number, we 

 jnow insert three illustrative figures of that very choice testaceous 

 production Helix Melanotragus, the Black-mouihed Helix of India. 

 Those figures are intended to represent the shell in three different 

 positions, in order to convey a more distinct idea of the species than 

 could possibly be given by a single figure in any point of view. 



The representations of this curious shell cannot fail to prove an 

 interesting addition to that of Helix Hsemastoma, the subject of the 

 preceding plate (132), since those two shells have been not unfre- 

 quently confounded with each other; and that even by conchologists 

 of no mean repute, Linnaeus had described the first of those two 

 shells under the specific name of Hsemastoma, and subsequent 

 writers, unwilling to separate a shell so nearly allied as the Helix 

 Melanotragus appeared to be, were induced rather to consider it as 

 the same species, or merely as a variety, than occasion error by des- 

 cribing them as two distinct shells. Lamarck, one of the latest 

 writers on this subject, allows the close affinity of those shells, 

 observing, however, that they must be specifically distinct. His 

 reason for entertaining this opinion is founded upon their difference 

 in form and also in colour, in which particulars, when attentively 

 considered, they are perceived to be dissimilar. Both are of a 

 globose-conic or conoidal form, and both are remarkably ventricose 

 or swollen in the first or greater whorl of the spire, but this ventri- 

 cosity is most striking in Helix Melanotragus, and in this shell it is 

 observed also, that the spire is rather more produced or pointed than 

 in Helix Hamastoma : the extreme whorls of the spire in Helix 

 Haemastoma, moreover, are of a rosy hue, while in the shell before us 

 the colour is pale yellow. 



