CYCLAS. Ill 



larger side of the shell. Muscular and pallial impressions 

 indistinct, the latter with a sinus. 



Animal suborbicular, its mantle freely open in front, and 

 anteally united posteriorly, to form a produced siphon, 

 divided at its extremity into two nearly equal tubes, which, 

 as well as the margins of the mantle, are not fringed. Foot 

 large, linguiform, very extensile. Labial palps long and 

 lanceolate. 



0, RivicoLA, Leach. 



Oval-globose, striated ; umbones obtuse ; dorsal area with a 

 small lunular impression ; ligament manifest. 



Plate XXXVII. fig. 1, 2, and (Animal) Plate Q. fig. ]. 



Cardium nux. Da Costa, Brit. Conch, p. 189 (in part). 



Tellina cornea, var. (i. Linn. Trans, vol. viii. p. 59. — Turt. Conch. Diction, 

 p. 180. 



Cardium corneum, (Thames var.) Mont. Test. Brit. p. 86. 



Cyclas cornea, Draparn. Moll. Ter. et Fluv. France, p. 128, pi. 10, f. 1, 2, 3. — 

 Brard, Coq. Ter. et Fluv. de Paris, p. 219, pi. 8, f. 2, 3. 



Cardium amnicum, Dorset Catalog, p. 32. 



Cyclas riiHCola, Leach, in Lam. Anim. s. Vert. (ed. Desh.) vol. vi. p. 267. — 

 Turt. Ditliyra Brit. p. 248, pi. 11, f. 13. — Flem. Brit. Anim. 

 p. 452.— Turt. Manual L. and F. W. Shells, p. 12, pi. 1, f. 1.— 

 Jenyns, Trans. Cambridge Phil. Soc. vol. iv. p. 294. — Gray, 

 Manual L. and F. W. Shells, p. 279, pi. 1. f. 1. — Brown, 

 lUust. Conch. G. B. p. 93, pi. 39, f. 16, 17, 18. — Pfeiffer, 

 Deutsh. Land und Sussw. Mol. p. 121, pi. 5, f. 3, 4, 5 — 

 SowERBY, Genera of Shells, Cyclas. — Kickx, Moll. Brabant, 

 p. 86.— Desh. Encyc. M6th. vol. ii. pt. 2, p. 36. — Sow. Con- 

 ch olog. Manual, f. 111. — Reeve, Conch. Systematica, pi. 62. 

 Hanley, Recent Shells, vol. i. p. 89, pi. 5, f. 90. 



Encyclop^die Method. Vers, pi. 302, f. 5. 



This large Cyclas (for, although of no peculiar magni- 

 tude as a shell, we know of no other species in its genus 

 which surpasses its dimensions) is of a nearly oval form, 

 and slightly, yet distinctly, inequilateral. It is moderately 

 ventricose, and comparatively strong and opaque : the swell 



