18 MOLLUSCA FROM THE CRAG. 



Erato,* Bisso, 1826. 



VoLUTA (spec.) Bon. 

 Cypr.ea. Motif. 

 IMarginella. De 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 ; apertui'e linear ; outer lip, in the adult state, thickened, 

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



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

 described by difl"erent authors either as Volutes, Cypraefe, or Marginellse, 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 plicse at the base of the columella, but are sufficiently characterized to 

 form a distinct and separate genus. 

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



VoLTJTA L^vis. Bon. Brit. Shells, t. 145, 1799. 



Cypk^a VOLUTA. Mont. Test. Brit. t. 6, fig. 7, 1803. 



Bulla diaphana,' juv. Test. Brit. p. 225, t. 7, fig. 8. 



VoLUTA CYPR.EOLA 1 Broc. Sub Appen. t. 4, fig. 10, a — b, 1814. 



Ekato cypr^ola. Risso. Hist. Nat. des princip. Prod, de I'Europe, torn, iv, pi. 7, fig. 85, 1826. 



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



— cypr^ola. Bvjard. Mem. de la Soc. Geol. de France, p. 302, 1837. 



Erato l.evis. S. Wood. Catalogue 1842. 



E. Testa subconoided, vel pi/riformi, politd ; spird prominuld, obtusiusculd ; an/ractibus 

 3 — 4 obsoletis ; aperturd angustatd, labro extus tnarginato, intus*denticulato ; colmnelld ad 

 basim pUcatd. 



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 calcai-eous 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 {qum prcesit rebus amatoriis,) given to this genus probably from 

 its connexion with Cyprsea (Cypris). 



