18 MOLLUSCA FROM THE CRAG. 



Erato,* Bisso, 1826. 



Voluta (spec.) Bon. 

 Cyprjea. Mont. 

 Marginella. Be France. 



Gen. Char. Shell ovate, more or less angulated or conoidal, generally smooth, 

 with a short, conical, distinct, but visible spire, and submammillated apex ; last whorl 

 large, inflated ; aperture linear ; outer lip, in the adult state, thickened, inflected, 

 and denticulated within j suture covered with enamel, base slightly emarginate. 



Only a few species of this group are as yet known, which have been variously 

 described by different authors either as Volutes, Cyprasae, or Marginellae, and, as far 

 as the shell may be a guide to its determination, it appears to come between the 

 last two genera, having the inflected lip of the former with the small but visible 

 spire of the latter. Seven recent species have been figured and described by Mr. 

 G. B. Sowerby, jun., in his ' Conchological Illustrations,' and these are all small 

 shells ; they have generally a few folds or plicae at the base of the columella, but 

 are sufficiently characterized to form a distinct and separate genus. 



1. Erato l^evis. Don. Tab. II, fig. 10, a — b. 

 Voluta l^ivis. Bon. Brit. Shells, t. 145, 1799. 

 Cypr^a voluta. Mont. Test. Brit. t. 6, fig. 7, 1803. 

 Bulla diaphana, juv. Test. Brit., p. 225, t. 7, fig. 8. 

 Voluta cypr^iola? Broc. Sub Appen. t. 4, fig. 10, a — b, 1814. 



Erato cypr^eola. Risso. Hist. Nat. des princip. Prod, de l'Europe, torn, iv, pi. 7, fig. 85, 1826. 

 Marginella Donovani. Payr. Cat. t. 8, fig. 25, 27, 1826. 



— cypr.eola. Bujard. Mem. de la Soc., Geol. de France, p. 302, 1837. 



Erato LiE vis. S. Wood. Catalogue 1842. 



E. Testa subconoided, vel pyriformi, politd ; spird prominuld, obtusiusculd ; anfractibus 

 3 — 4 obsoletis ; aperturd angustatd, labro extus marginato, intus denticidato ; columella ad 

 basim plicatd. 



Shell subconoidal or pear-shaped, smooth and glossy, with a short obtuse spire ; 

 volutions obsolete; outer lip thickened without, and toothed within; inner lip 

 slightly denticulated, with two or three folds upon the base of the columella. 



Axis, § of an inch. 



Locality. Cor. Crag, Sutton. 



Red Crag, Sutton. Recent, Britain. 



This species is rare, particularly in the Red Crag. It appears to agree in every 



respect with the recent British shell. The mantle enveloped the entire shell in its 



adult state, and the sutures of the spire are obliterated by an enamel-like calcareous 



deposit, which extends over the apex. The outer lip is thickened and contracted 



in the middle, with a row of very small teeth on the left side ; these enlarge into 



two or three folds at the base of the columella. A ventricose variety of this species 



is in Mr. Lyell's cabinet, from Touraine. 



* The name of one of the Muses (quce prasit rebus amatoriis,) given to this genus probably from its 

 connexion with Cypraa (Cypris). 



