LACUNA. 59 



Trans. Linn. Soc. vol. viii. p. '205. — Turt. Conch. Diction, 

 p. b1. 

 Helix lacuna, Mont. Test. Brit. p. 428, pi. 13, f. 6. — Maton and Rack. Trans. 

 Linn. Soc. vol. viii. p. 20L — Dillw. Recent Shells, vol. ii- 

 p. 917.— Wood, Lidex Testae, pi. 33, f. 70. 

 Nerita rufa, var. Mont. Test. Brit. Suppl. p. 151. 

 Turbo lacuna, Turt. Conch. Diction, p. L93, f. 87, f!8, 89. 



„ puteolus, Turt. Conch. Diction, p. 193, f. 90, 91. 

 Lacuna „ ' Turt. Zoolog. Journ. vol. iii. p. 191. — Brit. Marine Conch, 

 p. xxxviii. 

 „ Montacuti, Turt. Zoolog. Journ. vol. iii. p. 191. 

 Turbo fasciaius, Fleming, Brit. Animals, p. 300. 

 Natica lacuna, Fleming, Brit. Animals, p. 320. — Brit. Marine Conch, p. 150. — 



PoTiEZ and Mich. Galerie Douai, Moll. vol. i. p. 292. 

 Lacuna fasciata, Macgilliv. Moll. Aberdeens. p. 145, — Brit. Marine Conch, 

 p. 256, f. 84.— Brown, Illust. Conch. G. B. p. 128, pi. 10, 

 f. 54 (changed from Phasianella fasciata, p. 10). 

 „ sulcata, IMacgilliv. Moll. Aberdeens. p. 146 (fide Jeffreys from type). 

 „ Montagui, Brown, Illust. Conch. G. B. p. 128, pi. 57, f. 8. 



The members of the genus Lacuna require a studious 

 examination of long suites of examples collected from 

 various localities, in order to arrive at just conclusions 

 respecting the natural limits of each species. Our group- 

 ing together the very dissimilar forms that we have 

 included under the name of i^uteolus, is the result of such 

 an examination, and is forced upon us, contrary to our 

 preconceived ideas, by the observation of numerous con- 

 necting links between the several varieties. We pi-opose 

 to describe at large the typical form (the L. puteolus of 

 the " Zoological Journal," Turbo lacuna of " Turton''s 

 Dictionary"), and then to indicate the more peculiar 

 aberrations from its ordinary characteristics. 



The shape is nearly globular, and the shell, when adult, 

 is comparatively strong, and hence not particularly trans- 

 lucent. It is covered with a thin dull yellowish horn- 

 coloured skin, beneath which the surface is either of an 

 uniform livid Avhite, for the most part changing to an 

 obscure violet upon the spire, or else is alternately marked 



