BIVALVTA. 107 



1. Cyclas rivicola, Leach. MSS. 



Tellina cornea. Linn. Syst. Nat., ed. 12, No. 72, p. 1120 (part), 1767. 



— — Var. /3. Mat. and Rack. Linn. Trans., vol. viii, p. 59. 

 Cardium corneum. Mont. Test. Brit., p. 86, 1803, Var. 



— nux. Da Costa. Brit. Conch., p. 189. 



Cyclas cornea. Drap. Moll. Terr, et Fluv. Fr., p. 128, t. 10, figs. 1—3. 



— — Brard. Coq. Ter. et Fluv. des Env. de Par., p. 219, t. 8, figs. 2, 3. 



— rivicola. " Leach" in Lam. Hist, des An. s. Vert., t. v, p. 558, 1815. 



— — Turt. Brit. Biv., p. 248, pi. 11, fig. 13, 1822. 



Pfeiff. Land und Sussw. Moll., p. 121, pi. 5, figs. 3—5, 1821. 



— — Sowerby. Genera of Shells, No. 38, Cyclas. 



— — G. Sow., Jr. Conch. Man., fig. Ill, 1842. 



— — Fori, and Hani. Hist. Brit. Moll., vol. ii, p. Ill, pi. 37, figs. 1, 2. 



Ency. Metb., pi. 302, fig. 5. 



Spec. Char. Testa transversa, ovatd, tumiduld, crassiusculd, subaquilaterd, antice et 

 postice convexd ; concentrice striata ; ligamento cardinali conspicuo. 



Shell transversely ovate, somewhat tumid and strongs slightly inequilateral, 

 anterior and posterior sides rounded : finely striated concentrically ; cardinal area 

 conspicuous. 



Length, 1 inch. Height, J-ths. 



Locality. Southend (Warburton), Faversham {Trimmer). 



I have not myself met with this species as a fossil, but specimens in that state 

 have been obtained by Messrs. Warburton and Trimmer, from Faversham and 

 Southend. The specimens referred to are in the Museum of the Geological Society. 



2. Cyclas cornea, Linnaus. Tab. XI, fig. 2, a — b. 



Tellina cornea. Linn. Syst. Nat., ed. 12, No. 72, p. 1120, 1767. 



— — Chem. Conch. Cab., t. vi, p. 136, t. 13, fig. 133, bad. 



— — Penn. Brit. Zool., ed. 4, p. 89, pi. 49, fig. 36. 



— — Donov. Brit. Shells, vol. iii, t. 96, 1802. 



— rivalis. Mull. Verm. Hist., t. ii, p. 202. 



— stagnicola. Sheppard, Linn. Trans., vol. xiv, p. 150, 1825. 

 Cardium corneum. Mont. Test. Brit., p. 86, 1803. 



Cyclas cornea. Pfeiff- Deutsch. Land und Sussw. Moll., p. 120, t. v, figs. 1, 2, 1821. 



— — Turt. Brit. Biv., p. 248, pi. 11, fig. 14, 1822. 



— Gray. Man. Land and F.-W. Shells, p. 280, pi. 1, fig. 2, 1840. 



— — Jenyns. Trans. Camb. Philos. Soc, p. 295, 1831. 

 _ _ Phil. En. Moll. Sic, vol. ii, p. 30, 1844. 



— — Forb. and Hani. Hist. Brit. Moll., vol. ii, p. 1 13, pi. 37, figs. 3—6, 1849. 



— rivalis. Drap. Moll. Terr, et Fluv., p. 129, pi. 10, figs. 4, 5, 1805. 



— — Brard. Coq. Terr, et Fluv. Env. de Paris, p. 222, pi. 8, figs. 4, 5, 1815. 



— flavescens. Mac Gilliv. Moll. Aberd., p. 246, 1843, fide Forb. and Hani. 



Spec. Char. Testa transversa, ovatd, inflatd, tenui, etfragili, subincequilaterd ; postice 

 majiore, subquadratd, antice rotundatd, concentrice striata, margine ventrali leviter arcuatd, 

 apicibus obtusis. 



