330 OSTREADiE. 



seated : the edge of coronata, in adapting itself to the 

 substance on which it has been affixed, has become ser- 

 rated on one side. The nacre of the varieties cepa and 

 electrica are tinged, the former with lilac or rose colour, 

 the latter with yellow or rich amber colour ; in both 

 the perforation is peculiarly large and the lower valve 

 remarkably thin. 



Our larger examples are about two inches long and 

 rather less in breadth. 



The individuals received from North America, as the 

 ephippium of Gould (Invert, Massach. p. 138), have their 

 lower valve both within and without of a decided bluish 

 green, with generally an opaque white internal circum- 

 ference to the perforation : their upper valve displays a 

 yellow umbo on a ground otherwise devoid of colouring. 

 Possibly the examination of a sufficient number of ex- 

 amples might elicit such other features, as to warrant 

 the separation of the Transatlantic shell. 



The following account of the animal of Anomia epliip- 

 pium is from the pen of Mr. Clark : — 



" Animal suborbicular, mantle circular, the upper por- 

 tion, lining the convex valve, of very thin and pellucid 

 texture, except at the margin, which is thick and fleshy; 

 the under valve, or that lying on the flat valve, is also 

 thin, but has the appearance of being very fleshy from 

 having the lower portion of the ovarium soldered to it ; 

 both margins are clothed with a double fringe, and they 

 diminish in breadth as they approach the beaks, the 

 upper one passing round the aperture of the operculum 

 and there throwing out cilia, and with the under valve 

 fix themselves under the beaks. The margins on the 

 outer circle have long white or yellowish, thick set, very 

 pointed tentacular filaments, which may be seen protruded 



