SYNDOSMYA. 315 



Tellbia lineala, Turt. Conch. Diction, p. 168, f. 16 ; Dithyra Brit. p. 9d, pi. 7, 

 f. 1. — Flem. Brit. Anim. p. 435. — Brit. Marine Conch, p. 

 65.— Brown, Illust. Conch. G. B. p. 100, pi. 40, f. 15.— 

 Philippi, Neu. Conch. Tellina, ]A. 4, f. 6. — Hanl. in 

 Thesaur. Conch, vol. i. p. 233, pi. 56, f. 35, 36, and pi. BT^ 

 f. 46, 47. 



A Brazilian species, introduced hy Montagu as picked uj') hy 

 Mr. Bryer on the shore between Weymouth and Portland. In 

 this and the preceding cases of exotic species being enumerated as 

 British, there is no reason to suspect ivilfid deception : they were 

 probably taken frorn heaps of foreign ballast. 



SYNDOSMYA, Recluz. 



Shell thin, transversely more or less oblong- or elongated, 

 equilateral or inequilateral, slightly gaping at the extre- 

 mities, surface smooth, invested with a thin and deciduous 

 epidermis ; muscular impressions rounded or oblong ; pal- 

 lial sinus deep and wide ; hinge composed of an oblique 

 spathulate fulcrum in each valve, in the pit of which a 

 cartilage is lodged, and two distinct lateral teeth in one 

 or both valves ; primary teeth small or wanting ; ligament 

 rather short, partially external. 



Animal oblong, compressed, its mantle open throughout, 

 and finely fringed at the margin ; the siphons separated 

 throughout, long, slender, the upper one invested with a 

 fine wrinkled epidermis ; their orifices plain ; foot Ungui- 

 forra, large, apiculated ; labial tentacles triangular, some- 

 times obscure. 



The shells of this genus have been designated by so 

 many generic names, that some of our British concholo- 

 gists will hardly recognise them under the appellation we 

 have here adopted. Mactra, Amphidesma, Ligula, Ery- 

 cina, and Abra have at various times numbered them in 

 their ranks ; and, had the last-named designation ever 



