LACUNA. 351 



Adams, Helix lacuna and Nerita rufa (young) of Mon- 

 tagu, L. Montacuti (without bands) of Turton, L. Mon- 

 tagui of Brown, Temina Turtoniana, T. rufa, and T. va- 

 riabilis of Leach; L. sulcata of Macgillivray is the 

 young shell. Neither of the two earliest specific names 

 (parva and fasciata) appears to have been used by any 

 writer except those who respectively proposed them; 

 and they may therefore be regarded as obsolete. These 

 being disposed of, the name ought in strictness to be 

 Montacuti, which was given by Turton in the ' Zoological 

 Journal ' (vol. iii. p. 191) to the typical form; his Turbo 

 or L. puteolus is the variety which I have noticed as 

 expansa. But it does not seem necessary, or desirable, to 

 change the name adopted by the authors of the ' British 

 Mollusca.' 



K* 4. L. pALLi'DULA*,(JDa Costa.) ^ -6^ 



Nerita pallidulus, Da Costa, Brit. Conch, p. 51, t. iv. f. 4, 5. L.patti- 

 . dula, R & H. iii. p. 56, pi. Ixii. f. 1, 2, and (as L. patula) f. 3, 4. 



BODY whitish : mantle tumid at the margin : head nearly 

 cylindrical, projecting a little beyond the foot ["the upper 

 part of the neck has two short flake-white diverging lines im- 

 bedded in the ground-colour." Clark] : tentacles resembling 

 in miniature the leaves of the water-flag : eyes rather small : 

 foot double-edged in front, behind which it is somewhat con- 

 tracted, thickened and opaque towards the edges, and ending 

 in an extremely short pointed tail ; sole grooved lengthwise : 

 appendages nearly of the same shape as the tentacles, but 

 smaller and very much shorter, although extending beyond 

 the foot. 



SHELL somewhat triangular, largely and obliquely expanded 

 in front, rather thin, opaque, and glossy : sculpture, fine but 

 irregular striae in the line of growth, which are for the most 

 part concealed by the epidermis, and are more conspicuous 

 just below the suture; there are also a few remote and scratch- 

 like lines in a spiral direction: colour pale yellowish-green: 

 epidermis not very thin, resembling oilskin : spire very small 



* Palish. 



