CHEMNITZIA. 429 



very large auricles, which in progression are used as feelers ; 

 the margins of the foot are often reflexed, as if to embrace the 

 sides of the shell ; it is long, and when fully extended reaches 

 to the third basal volution, and ends in a needle point ; some- 

 times on each side there is a row of small flake-white spots ; 

 it carries on a simple upper lobe, scarcely distinguishable 

 from the mass of the foot, a light corneous, thin, obliquely 

 striated pyriform operculum. 



The animal marches with rapidity, and is far more active 

 than the C. inter stincta. It inhabits, with the variety " cla- 

 thrata," a peculiar district of shelly mud, between the lamina- 

 rian and coralline zones in ten fathoms water, off Teignmouth. 



That this is Montagu's Turbo indistinctus is scarcely doubt- 

 fid ; he says that his examples have six volutions, and no fold 

 in the aperture that is the number of the ordinary run of 

 specimens; but both the type and variety, when very fine, 

 have 6^ to 8 turns, as our magnificent series will show. 



There can be no doubt of the C. indistincta being distinct 

 from the C. interstincta ; we, in our first accounts, thought 

 otherwise ; but the greater number of volutions, the invariable 

 absence of a tooth, the much more diffused lattice-work of the 

 former, and the specific differences of the animals, afford 

 decisive marks of distinction. 



We have examined more than twenty live specimens of the 

 typical species, in comparison, often in the same vase, with 

 forty of the variety " clathrata" which only differs from the 

 type, as regards the animal, in having the posterior volu- 

 tions pale pink, giving the shell the appearance of being of a 

 still paler pink hue, but in fresh shells the colour is a dull 

 pearly white : this difference in the animals is probably de- 

 pendent on food. Another variation, perhaps the effect of the 

 same cause, is, that the contour of the variety is somewhat 

 less slender than the type; but the similar number of the 

 volutions, the character of the lattice-work, and the want of 

 the tooth in the aperture of both, together with the apparent 

 identity of the animals, forbid the differences I have noticed 

 to be considered of more value than of mere and not uncom- 

 mon variations. 



