256 MOLLUSCA FROM THE CRAG. 
Locality. Red Crag, Sutton. 
Clyde Beds, and Irish Drift. 
Recent, Mediterranean, Britain. 
This shell, I believe, has not been met with in the Coralline Crag: in the Red 
Crag it is not by any means abundant, and always in a fragmentary state. In my best- 
preserved specimen, the anterior termination is rather more rounded than that of 
the recent species to which it is assigned, but I have not enough to say if such be a 
constant character.* 
3. SouEN ENsIs, Linneus. Tab. XXV, fig. 6, a—/. 
Sorzn Ensts. Linn. Syst. Nat., ed. 12, p. 1114, No. 35, 1767. 
—_  — Poli. Test. Sicil., vol. i, p. 18, t. 11, fig. 14, 1791. 
—_ — Broce. Conch. Foss. Subap., p. 479, 1814. 
—_- — Gould. Invert. Massach., p. 29, 1841. 
- — Desh. Exp. Scient. Alger., p. 184, pl. 11, figs. 1—4. 
= = Nyst. Coq. Foss. Belg., p. 44, pl. 1, fig. 4, a, 6, 1844. 
——— Tovén. Ind. Moll. Scand., p. 49, 1846. 
— — 2? Grateloup. Cat. Zool. Invert. Gironde, p. 68, No. 819, 1838. 
—————— Sismonda. Syn. Ped. Foss. Invert., p. 23, 1847. 
— — Forb. and Hanl. Hist. Brit. Moll., vol. i, p. 250, pl. 14, fig. 2, 1848. 
— curvus. List. Hist. Conch., t. 311, fig. 257. 
— eEnsirormis. S. Wood. Catalogue, 1840. 
= = J. Sowerby. Min. Conch., t. 642, fig. 1. 
— a 2? Conrad. Foss. Med. Tert., p. 76, pl. 43, fig. 8, 1845. 
— Havsmannt? Goldf. Pet. Germ., vol. ii, p. 277, pl. 159, fig. 6, a—c, 1842. 
Spec. Char. Testa lineari, arcuatd, extremitate anticd curvatd, non marginatd ; in 
valvdé sinistrd unidentato, in alterd bidentato. 
Shell linear, curved, anterior extremity rounded, not marginated; one cardinal 
tooth in the left valve, and two in the right. 
Length, 3 inches. Height, 3 inch. 
Locality. Cor. Crag, Sutton, Ramsholt, Sudbourn. 
Red Crag, Sutton, Walton Naze. 
Trish Drift (Fordes). 
Recent, N. E. Coast of America, Brit. Seas, Mediterranean, Sea of Okhotsk (J/iddendorf ). 
This species first appears in the Coralline Crag, where it is not very abundant ; 
* Since the above was written, I have obtained an imperfect specimen (fig. 7, a, 6) of what appears to 
belong to this species, judging from its linear character, in which the muscular impressions are, like those 
of S. gladiolus, at a greater distance from the anterior margin, and which I first imagined to be a tangible 
distinction. I now believe the two may be specifically united. 
