PSAMMOBIA 279 



so often cast on shore. It occnrs at Guernsey and Exmontli 

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

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

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

 drew and E. F.) ; Tenby (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, TurtOU. 



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

 costellse or elevated strife. 



Plate XIX. %. 5. 



Psammohia costidata, Turt. Dithyra Brit. p. 87, pi. 6, 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. b9. — Philippi, Moll. Sicil. vol. ii. p. 21. 

 — Philippi, Neu. Conch. Psammohia, 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 



