132 GASTROCn^NID.^. 



G. MODioLiNA, Lamarck. 



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



Mya diibia, 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. — Woou. 

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

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



Mya pholadia, Mont. Test. Brit. vol. i. pp. 28, 559, and Suppl. p. 20. 

 Pholasfaba, Pulteney, Hutchin's Hist. Dorset, p. 27. 

 Mytihis amliguus, Dillw. Recent Shells, vol. i. p. 304. 



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

 Genera Shells, Gastrochajna, 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. 

 „ pJioladia, Turt. DithjTa Brit, p. 18, pi. 2, f. 8, 9. — Magazine of 



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

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

 „ fiians, Flem. Brit. Anira. p. 458. 



„ dtibia, Desh. Traite Elem. Conch, pi. 2, f. 4, 5. — Philu'I'i, in 



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



The paucity of known species belonging to the genus 

 Gastrochana, gives an interest, independent of peculiarities 

 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 

 rounded 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 which 

 are decidedly prominent and curving forward, are not 



