PSAMMOBIA. 279 



so often cast on shore. It occurs at Guernsey and Exmouth 

 (Clark, Metcalfe, S. H.) ; Falmoutli (Jeffreys) ; Portland 

 in fifteen, Plymouth in twenty-five, and Penzance in 

 twenty fathoms, where a white variety was taken (M'An- 

 drew and E. F.) ; Tenhy (S. H.) ; Cardigan Bay (M'An- 

 drew) ; Bantry in fifteen fathoms (M'Andrew) ; Cork, 

 Youghal (Humphreys and Jeffreys) ; Oban, and lochs of 

 the west of Scotland (Jeffreys) ; Outer Hebrides (M'An- 

 drew) ; Zetland in depths from five to fifty fathoms, often 

 in shelly gravel (M'Andrew and E. F.). On the whole, it 

 appears to be a western shell. It occurs fossil in the co- 

 ralline crag. 



P. COSTULATA, TurtOH. 



Smooth, except at the posterior end, where it is rayed with 

 costellae or elevated strioe. 



Plate XIX. fig. 5. 



I'sammohia costulata, Turt. Dithyra Brit. p. 87, pi. C, f. 8. — Flem. Brit. Anim. 

 p. 437. — Brit. Marine Conch, p. 62. — Brown, Illus. 

 Conch. G. B. pp. 102, 133, pi. 39, f. 34.— Hanl. Re- 

 cent Shells, p. 59. — Philippi, Moll. Sicil. vol. ii. p. 21. 

 — Philippi, Neu. Conch. Psammobia, pi. 1, f. 3, 4. 



discors, Philippi, Moll. Sicil. vol. i. p. 23, pi. 3, f. 8. 



This small species, which is most closely allied in shape 

 and general character to Tellinella, is principally distin- 

 guished from it by the sculpture upon its posterior side. 

 It is rather thin, but not transparent, nearly equilateral, and 

 moderately convex ; the chief profundity is at the umbonal 

 region. The outline is nearly oblong ; the front extremity 

 is rounded and distinctly attenuated, and the hinder (from 

 the convexity of the posterior edge) is only bluntly sub- 

 biangulated. The external surface is almost devoid of 

 lustre, and in the adult is closely set with concentric, irre- 

 gularly-disposed wrinkles, which become obsolete upon the 



