CSl MOI.LUSCA. 



pression under the (leak. Two aud a half inches long. Inhabits the British 

 and Mediterranean seas. 



Cyprina Islandica. — The Islandic Cyprina. — Plate Ixxviii. fig. 22. Siibor- 

 bicular, convex, strong, irregularly striated ; covered with a deep black- 

 brown epidermis j white within. Three and three-fourth inches long. 

 Inhabits the Atlantic ocean and British seas. 



Exoleta Orbiculata. — The Orbicular Exoleta. Plate Ixxviii. fig. 23. Or- 

 bicular, strong, with regular coarse, close set transverse striae ; generally 

 white, or pale brown, with sometimes three or four brown radiations eman. 

 ating from the umbo, and terminating in the margin ; inside white. Tw*» 

 inches long. Inhabits the European seas. 



Las<Ba rubra. — The Red Lassea. Plate Ixxviii. fig. 16. Convex, smooth, 

 glossy, pellucid, reddish.pink. Fourth of an inch long. Inhabits the British 

 seas. 



Galathea radiata. — The Rayed Galathea. Plate Ixxviii. fig. 20. Some- 

 what trigonal, gibbous towards the base ; covered with a yellowish-green 

 thin epidermis, beneath which it is radiated with pale chestnut. Three and 

 a half inches long. Inhabits the rivers of Ceylon. 



Cyrena fluminea. — The River Cyrena. Plate Ixxix. fig. 1. Heart-shapei 

 gibbons, greenish.brown ; transversely sulcated ; variegated with white and 

 violet in the inside. One inch long. Inhabits the rivers of China. 



Cyclas cornea. — The Horny Cyclas. Plate Ixxix. fig. 2. Suborbicular, 

 convex, thin, pellucid, with fine concentric striae ; covered with a horn- 

 coloured epidermis ; bluish-white within. Three-fourths of an inch long. 

 Inhabits rivers of Europe. 



Crassina Scotica. — The Scottish Crassina. Plate Ixxix. fig. 3. Somewhat 

 heart-shaped, a little compressed, with regular parallel grooves and ribs ; 

 impressions under the beak lanceolate ; covered with a yellow-brown epi- 

 dermis ; inside pure white ; margin broad and plain. One inch lopg. In. 

 habits the Scottish and Devonshire coasts. 



Capsa lavigata. — The Polished Capsa. Plate Ixxix. fig. 4. Triangular, 

 sub-equilateral, obsoletely striated transversely ; covered with a greenish, 

 yellow epidermis ; inside violet towards the umbones. Two inches long. 

 Inhabits the Indian ocean. 



Donax trunculus. — The Truncated Donax. Plate Ixxix. fig. 5. Oblong, 

 glossy, finely striated and radiated longitudinally ; transversely banded with 

 purple ; white and clouded with p\irple within ; margin crenulated. One 

 inch and a quarter broad. Inhabits the seas of Europe. 



Lucina unduta. — The Waved Lucina. Plate Ixxix. fig. 7. Orbicular, 

 thin, convex, undulated, with fine irregular striae ; pale straw-coloured 

 yellow, and white in the inside ; margin glossy and plain. 



Mysia roiundata. — The Rounded Mysia. Plate Ixxix. fig. 6. Orbicular, 

 somewhat conve.x, thin, sub.pellucid, and obscurely striated; umbones 

 small and oblique. Three quarters of an inch long. Inhabits the British 

 seas. 



Corbit fimbriata. — The Fringed Corbis. Plate Ixxix. fig. 8. Very thick, 

 white, transversely oval, gibbous, longitudinally striated, with transverse, 

 undulated furrows ; the margins crenulated ; with depressions somewhat 

 lanceolate. Two inches and a half broad. Inhabits the Indian ocean. 



Arcopagia crassa. — The Thick Arcopagia. Plate Ixxix. fig. 9. Sub- 

 orbicular, strong, thick ; upper valve fiat ; with coarse, thick-set, transverse 



