The two varieties of _A. virginea_ on this plate, are still more removed from the type of the species than those last figured; they are both much larger in size, and var. 4 presents a slight difference of formation, in having the basal volution somewhat carinated round the middle; but as in every other essential character it agrees with the rest, I have refrained from separating it as a distinct species. The four varieties I have now illustrated of _Ach. virginea_, tend to establish, in a very complete manner, the correctness of the principles on which I have framed the specific characters of this genus; here are four shells, with a total difference in the colouring of each, yet all agreeing in the same formation. It should be observed likewise, that _A. pallida_, figured at pl. 41 of this work, and _A. virginea_, var. 4, are nearly the same in colour, while in formation they are completely at variance. I do not think it has been hitherto remarked, that the elegant green lines which ornament the common variety, are only _external_; they resemble, in this respect, the epidermis of other shells, for they may be taken off by a knife without any injury to the enamel. M. Ferrusac has figured several other varieties in his beautiful work on Land Shells. * * * * * Pl. 124 [Illustration] LICINIA Crisia. * * * * * GENERIC CHARACTER.--See Pl. 15. * * * * * SPECIFIC CHARACTER. _A. mas. Alis anticis falcato-acuminatis, fuscis, fascia media margineque postico flavo; posticis infra flavescentibus colore griseo variis, basi maculis 4 fulvis._ _Fem. Alis infra albentibus colore griseo variis; anticis integris, supra fuscis, fascia media margineque postico albentibus; posticarum basi maculis 4 fulvis._ _Male._ Anterior wings angulated, brown, with a central band and hind margin yellow; posterior beneath yellowish marbled with grey, base with 4 fulvous spots. _Female._ Anterior wings entire, above brown, with a central band and hind margin whitish; all the wings beneath whitish marbled with grey; base of the posterior with 4 fulvous spots. Pieris Crisia. _Godart. En. Meth._ _p._ 197. _Male._ _Drury_, _v._ 3. _pl._ 37. _f._ 1. 2? * * * * *