132 GASTROCHiENIDiE. 



G. MODioLiNA, Lamarck. 



Plate II. figs. 5, 6, 7, 8 ; and (animal) Plate F. f. 5. 



Mt/a duhia, Penn. Brit. Zool. ed. 1777, vol. iv. p. 82, pi. 44, f. 19.— Donov. Br. 

 Shells, vol. iii. pi. 108.— Dorset. Catal. p. 27, pi. 1, f. 11.— Linn, 

 Trans, vol. viii. p. 33. — Turt. Conch. Diction, p. 104. — Wood. 

 General Conch, p. 102, pi. 25, f. 2, 3. 

 Chama parva. Da Costa, Brit. Conch, p. 234. 



Ml/a phuladia, Mont. Test. Brit. vol. i. pp. 28, 559, and Suppl. p. 20. 

 rholiis fala, Pulteney, Hutchin's Hist. Dorset, p. 27. 

 Rlijtihis ambiijuus, Dillw. Recent Shells, vol. i. p. 304. 



Gastrochcena modiolina. Lam. Anim. s. Vert. ed. 2, vol. iv. p. 49. — Sow. 

 Genera Shells, Gastrochsena, f. 1,2; Conch. Manual, 

 f. 52.— Reeve, Conch. System, pi. 20, f. 1, 2.— 

 Hanl. Recent Shells, p. 10.— Brit. ]Marine Conch. 

 p. 33. 

 „ pholadia, Turt, Dithyra Brit, p. 18, pi. 2, f. 8, 9. — Magazine of 



Nat. Hist. vol. vi. p. 404, f. 52. — Brown, 111. 

 Conch. G. B. p. 116, pi. 48, f. 13, 14. 

 „ Mans, Flem. Brit. Anim. p. 458. 



„ dubia, Desh. Traite Elem. Conch, pi. 2, f. 4, 5. — Philippi, in 



Wiegman Archiv. Natur. 1845, pi, 7, f. 1. 



The paucity of known species belonging to the genus 

 Gastrochcena^ gives an interest, independent of pecuharities 

 of habitat and infrequency of occurrence, to the only one 

 inhabiting our British seas. This is obliquely oval-oblong, 

 in shape, cuneiform in convexity, being ventricose in front, 

 and compressed behind, rather thin and fragile, and of a 

 somewhat opaque white. The surface, which in living 

 examples is very slightly glossy, is merely marked with fine 

 concentric wrinkles, which are chiefly evident in front and 

 below. The large hiatus, which is fig-shaped, being 

 roianded in front, and produced and tapering behind to an 

 acuminated point, occupies nearly the entire ventral mar- 

 gin ; the shell is strictly closed at its posterior termination. 

 The sides are excessively unequal, but the umbones mIiIcIi 

 are decidedly prominent and curving forward, are not 



