178 OYSTERS, AND ALL ABOUT THEM. 



riblets of equal size : inside grooved and striate accord- 

 ingly. 



HABITAT: N. of Hebr., 170-189 f. (C. and T.), F. 

 Norway (Sars and others) ; Messina (Seguenza) ; ! E. Hol- 

 land (Herklots) ; Brittany (Recluz and others) ; Arcachon 

 (Lafont). ! Not uncommon from Shetland to the Channel 

 Isles in 7-82 fathoms, on a sandy bottom mixed with 

 gravel ; and the variety is equally diffused. This species 

 occurs as an upper tertiary fossil in the Scotch glacial 

 deposits, and also in the Red and Coralline Crag. It is a 

 native of the Icelandic and Scandinavian coasts, and 

 Me Andrew has taken it in Vigo Bay, at a depth of only 8 

 fathoms. 



The shell varies greatly in size and proportions, as 

 well as in colour and the number of ribs. My largest 

 specimens are one inch and two-tenths long, and nearly 

 the same in breadth. Sometimes the breadth slightly 

 exceeds the length. Young shells are proportionally 

 longer than old ones. 



In the former the so-called " eyes ' are perceptible, 

 through the semitransparent shell, many years after the 

 animal has ceased to exist. The fry are not sculptured, 

 but perfectly smooth, and the lower valve is nearly flat and 

 smaller than the other. Miiller noticed the way in which 

 he presumed this scallop procures its food, viz., by rapidly 

 opening the valves of its shell and clapping them together 

 with an audible noise ten or twelve times in succession. 

 It then kept them wide open, and for a much longer time 

 than suited the patience of the great zoologist. By this 

 violent agitation of the water a fresh supply of animalcule 

 may be brought to its insatiable maw. He adds that it can 

 squirt the water out of a vessel half an ell high ; but I have 



