SYNDOSMYA. 323 



mas) ; Zetland, in from five fathoms, as at Balta Sound, 

 to one hundred, as it occurred at twenty-five miles east from 

 Noss (MacAndrew) ; Skye in twenty fathoms, Loch Fyne 

 in fifty fathoms (MacAndrew and E. F.) ; Mull of Gal- 

 loway (Beechey) ; " Found on all sides of Ireland : thrown 

 ashore at Magilligan, Belfast bay and Dublin coast ; 

 dredged by Mr. Hyndman in twenty fathoms, in Belfast 

 bay, and from fifty fathoms off the South Rock, Down. 

 Found in spring in the stomachs of haddocks and flat fish 

 along the eastern coasts" (Thompson). In sixty fathoms 

 off Cape Clear (MacAndrew). 



Abroad this species ranges from the seas of Norway to 

 the ^Egean. As a fossil it occurs in the coralline crag. 



S. TENUIS, Montagu. 



Subtriangular, abnost equilateral ; breadth and length nearly 

 equaL 



Plate XVII. fig. 11. 



Mactra tenuis, Mont. Test. Brit. p. 572, pL 17, f. 7. — Linn. Trans, vol. viii. p. 

 72. — Dorset Catalog, p. 33. — Turt. Conch. Diction, p. 84. — 

 Flem. Brit. Anim. p. 433. — Dillw. Recent Shells, vol. i. p. 

 142. — Index Testaceolog. pi. 6, Mactra, f. 26. 

 Amphidesma tetiue. Lam. Anim. s. Vert. (ed. Desh.) vol. vi. p. 128. — Turt. 

 Dithyra. Brit. p. 53.— Flem. Brit. Anim. p. 432.— Mac- 

 GiLLiv. Moll. Abcrd. p. 293. — Brit. Marine Conch, p. 5h, 

 f. 24.— Brown, 111. Conch. G. B. p. 105, pi. 45, f. 2.— 

 Delessert, Recueil Coquilles, pi. 4, f. 6. — Hanl. Recent 

 Shells, p. 42. 

 Syndosmya tenuis, Recluz, Revue Cuv. Zool. 1843, p. 366. — Recluz, in Chenu's 

 111. Conch. Syndosmya, p. 3. 



This small Syndosmya is nearly equilateral, subtrian- 

 gular, very thin and fragile, somewhat translucent, and 

 under a very delicate sallow and slightly concentrically 

 wrinkled epidermis, of a dirty white hue, occasionally 

 somewhat iridescent, and but rarely glossy. The surface is 



