QP 



CHAPTER XVII. 



INCONGRUITIES. — LIMA. ITS WOVEN NEST. PECTEN. ITS OCELLI. — ITS 



MOVEMENTS. SPECIES. — OSTR^A. ' ONLY ONCE A YEAR.' — OYSTER- 

 BEDS. — ANOMIA. 



OSTRu^AD^. 



Scallops and Oysters ! The most active and most sedentary 

 of molluscs : the smart and merry Pecten^ with the grave 

 and placid Oyster, the time-honoured symbol of all that is 

 heavy, dull, and inanimate ! One would suppose that the 

 only excuse for grouping them together would be, that both 

 are articles of food. The animals of one are free, of the 

 other are attached, by their shells growing on to each other 

 and the rocks. The one has a foot and a circle of tentacles, 

 while in the other the foot is wanting and the mantle is 

 without ornaments; the shell of the one is regular, while 

 that of the other is rough and uneven. Yet there are spe- 

 cies and genera which, in one character or another, form 



