446 MOLLUSCA. VENERIDiE. Cvtherea. 



519- C. orbiculata. — Orbicular, compressed and cancellated; 



beaks small, with a minute cordiform impression in front. 



Venus orb. Mont. Test. Brit. Sup. 42. t. xxix. f. 7— Cyprina orbiculata, 

 Turt. Biv. Brit. 138 — Dunbar, Mr Laskey. 



Diameter fths of an inch ; white; margin plain ; two approximating teeth, 

 and one transverse, and rather remote where the margin is angular. 



EXTINCT SPECIES. 



1. C. lentiformis Orbicular, depressed, with concentric, reflected, minute, 



imbricated ridges ; posterior slope depressed, terminated by an angle at the 



margin Venus exoleta, Park. Org. Rem. iii. 189. V. lent. Sower. Min. 



Conch, t. cciii — Crag. 



2. C. Scutellaria Manl. Geol. 263. t. xxv. f. 2 — Plastic Clay. 



G£N. CXXVIII. VENUS.— Shell suborbicular, inequilater- 

 al ; hinge with three diverging teeth in each valve, the mid- 

 dle one in the left valve strong and bifid. 



* Margin within crenulated. 



— 520. V. verrucosa. — Shell tumid, heart-shaped, with numer- 

 ous concentric ridges, broken into tubercles by longitudinal 

 grooves at both extremities. 



Pectunculus omnium, crassissimus, List. Conch, t. cclxxxiv — Concha 

 cinerea, Borl. Corn. 275. t. xxvii. f. 32. — V. ver. Linn, Syst. i. 1 130. — 

 V. ervcina, Perm. Brit. Zool. iv. 94. t. liv. f. 48 — V. ver. Don. Brit. 

 Shells, t. xliv. Mont. Test. Brit. 112. Turt. Biv. Brit. 140 Eng- 

 lish and Irish shores. 



Length two inches and a quarter, breadth a little more ; rufous ; strong ; 

 depression before the beaks heart-shaped, the posterior, or cartilage depres- 

 sion, distinctly displayed only on the left valve ; the ridges are sharp, reflect- 

 ed and striated, and, towards the beaks the furrows are striated longitudinal- 

 ly ; the margin crenulated within. 



521. V. cassina. — Shell slightly compressed and heart-shaped, 

 with numerous concentric entire ridges. 



Linn. Syst. i. 1130 V. erycina worn, Penn. Brit. Zool. iv. t. liv. f. 48. 



A V. lactea, Don. Brit. Shells, t. cxlix V. cass- Maton and Rue 



kett, Lin. Trans, viii. 79. t. ii- f. 1. Turt. Biv- Brit. 141. t. ix. f. 1 — 

 Various parts of tjje coast. 

 Diameter about two inches ; whitish ; ridges irregular in size, curving to- 

 wards the hinge ; left valve at the ligament depressed and striate ; margin 

 sometimes very obtuse — This species is distinguished from the preceding by 

 ■being less tumid, and by the ridges being entire. 



522. V. reJJexa. — Shell compressed, dorsal margin behind the 



beaks nearly straight ; concentric ridges rising into thin plates 



xctrally, where they are waved and deflected. 



Laskey, Wern. Mem. i. 384. t. viii. f. 1. Mont. Test. Brit. Sup. 40. 

 Flem. Encyc. Edin. vii. 95. t. ccvi. £ 1. Turt. Biv. Brit. 142. t.x. f. 1, 



2 Various parts of the coast from Devon to Zetland. 



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