FAMILY 1. MELANIANA. 123 
Pl. CXCIV. Fig. 5. (fossil.) 
MELANIA MARGINATA, Lamarck, Anim. sans vert., new edit., vol. vill. 
p- 445. Ann. du Mus., vol. iv. p. 130, and vol. viii. p. 60. f. 4. 
Deshayes, Désc. des Coquilles fossiles, vol. 11. p. 114. pl. 14. f.1 to 4. 
Bulimus turricula, Bruguiére. 
MELANOPSIS, Lamarck. 
Testa fusiformis, vel conico-cylindracea, epidermide nigerrima interdum 
induta; apice acuto, sepe decorticato; columella levi, superneé 
seepe incrassata, inferné subtruncata ; apertura oblonga, supra acuta, 
nonnunquam subcanaliculata, infra profundé emarginata ; labro pau- 
lulum reflexo. Operculum corneum, spirale, parvum. 
The Melanopsides were separated by Lamarck from the Melanie, for 
the same reason that induced him to distinguish the Achatine trom the 
Bulimi, namely, on account of a truncature of the columella. He then 
proposed another genus, Pirena, for such of them as exhibit a swollen 
callosity on the upper part of the columella, and have the upper portion 
of the aperture emarginated with a sinus as well as the lower. The 
value of this distinction has, however, been long ago nullified by the 
discovery of intermediate variations of growth; the genus Pirena was 
abandoned first by De Férussac, afterwards by Sowerby, and we see no 
necessity for reviving it. The basal sinus, an indication of which may 
be traced in many of the Melanie, is very characteristic in the Melanop- 
sides, and accounts for the early naturalists having associated these shells 
under the significant title of the freshwater Buccina ; whilst Linnzus, for 
the same reason, referred the well-known Melanopsis atra to his genus 
Strombus. 
The shell of Melanopsis may be described as being either fusiform or 
conically cylindrical, and generally covered with a very black epidermis ; 
the apex is sharp, but often decorticated ; the columella is smooth, often 
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