26 MOLLUSCA FROM THE CRAG. 



1. Terebra inversa. Nyst. Tab. IV, fig. 3, a — b. 



Tekebra inversa. Nyst. Coq. foss. de Beige, p. 581, pi. 44, fig. 9, 1844. 

 — IIETEROSTROPHA. S. Wood. Catalogue 1842. 



T. Testa, turritd,subidatd, sinistrorsd; longitudinaliter plicatd, anfractihus sitb-planulatis, 

 prope suturam appressis, in/erne convexiusculis ; aperturd ovatd sub effusd; columella contortd ; 

 labro acuto, intws nitido. 



Shell fusiform, turriculate, sinistral, with a rather obtuse apex ; whorls nearly flab 

 longitudinally plicated; aperture ovate; outer lip sharp, with a shghtly recurved canal. 



Axis, nearly % of an inch. 



Locality. Cor. Crag, Gedgrave. 

 Red Crag, Sutton. 



In a communication from M. Nyst, he says that the Belgian shell, which I have not 

 seen, is perfectly identical with that from the Crag. I have therefore given his name ; 

 mine, being without desci'iption, can be considered only as provisional. My specimens 

 are few, and not in good condition ; one of the most perfect shows a ridge running 

 round the upper part of the volution, like that in T.pertusa, but not so distinct ; neither 

 are the volutions so flat as in that shell, and it appears to have a longer canal. 



2. Terebra canalis. Tab. IV, fig. 4. 



Terebra canalis. S. Wood. Catalogue. 



I have only three or four imperfect specimens of what stands under this name in 

 my Catalogue. It much resembles the preceding in the length of its canal and form 

 of its volutions, and may possibly be only a dextral variety ; but better specimens than 

 I possess are necessary for such a determination. 



The figure above refeired to is a restored form by the union of two imperfect 

 specimens. 



Cassidaria,* Lam. 1812. 



MoKio. Monff. 1810. 

 EcHiNORA. Schum. 1817. 



Gen. Char. Shell ovate, ventricose, with a short turreted spire, last whorl much 

 inflated, for the most part spirally grooved or tuberculated ; aperture large, termi- 

 nating anteriorly in a slightly recurved canal ; outer lip thickened, reflected, and 

 dentated within, in the adult state ; inner lip broad and expanded over the umbilicus, 

 with part of its lower edge free. Operculum (?) 



This genus in most of its characters resembles Cassis, but is distinguished by 

 its rather lengthened and less suddenly recurved canal. In Cassis it is emarginate, 

 short, and reflected. The Crag shell was first placed in the latter genus in the 

 ' Mineral Conchology,' the canal not having been seen by the author of that work. 



This genus is rather indicative of tropical or subtropical regions, and several species 

 have been described from the Eocene as well as from the Meiocene formations of Europe. 



* Etytn. Cassida, a helmet. The name of Mono appears to have priority of date. Cassidaria having 

 been used in my Catalogue, it is not thought necessary to alter it. 



