PULMONATA. 137 



This genus was first separated by Adanson, and afterwards by Humphrey, for shells 

 previously referred either to Voluta or Mitra. Subsequently Lamarck defined it more 

 exactly under the present name, by which it is now known. The animal resembles that 

 of Cyprcea in all essential particulars, and like it, is furnished with lobes to the mantle, 

 which can be extended over the shell so as to cover the spire, which thus acquires an 

 enamel-like covering resembling that of the Cowries. The condition of the spire, th 

 number and the arrangement of the columellar plaits, and the simple or crenated state 

 of the outer lip, have been used as characters for the separation of the Marginella into 

 various genera ; but these divisions do not appear to be warranted by generic dis- 

 tinctions in the animals and consequently, have not been generally adopted, but have 

 been regarded as sections merely of the present genus. Mr. G. Sowerby {Gen. Shells), 

 has suggested that the Marginella may be classed under two natural sections ; the 

 first comprising the species in which the spire is distinct, the columella furnished 

 with four folds at the base, and the outer lip characterised by a thick fold-like 

 border along the outer margin ; the other consisting of the species in which the 

 spire is short, almost concealed, the columellar plaits more numerous, the an- 

 terior plaits being the larger, and the outer lip but slightly thickened. The first 

 section corresponds with Glabella (Swain.) and Phanospira (Hinds); the latter represents 

 Persicula (Schum.), Volutella, Gibberula, Marginella (Swain.), and Cryptospira (Hinds). 

 The recent Marginella are numerous ; they chiefly inhabit the tropical and sub- 

 tropical seas, where they are found in shallow waters ; they appear to abound on the 

 coasts of Africa, and some few small species, belonging to the second section, are found 

 in the Mediterranean. In the fossil state they first appear during the tertiary epoch. 

 In the French eocene beds, eleven species occur, of which seven have been described 

 by Lamarck andDeshayes; and of these, several are found in England, Germany, and 

 Belgium. Six species from the corresponding formations in Alabama (U.S.), have also 

 been described by Conrad and Lea: and in the more recent deposits in Europe and the 

 United States, twenty additional species have been found. 



Section A. Spire apparent. 



No. 80. Marginella eburnea. Lamarck. Tab. XVIII, figs. 1 a — c. 



Marginella eburnea, Lamk. 1803. Ann. du Mus., vol. ii, p. 61, No. 1; and vol. vi, 



t. 44, fig. 9. 



— — Roissy. 1804. Buff. Moll., vol. vi, p. 9, No. 4. 



— — Lamk. 1822. Hist, nat., vol. vii, p. 359, No. 15. 



— — Brogn. 1823. Sur les ter. tert., du Vicent., p. 64, No. 1. 



— — Deft. 1823. Diet, des sci, nat., vol. xxix, p. 145. 



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