OF BIVALVED SHELL-FlSH. 555 



fo common in the rivers of the tropical climates, as to fee oyfters hang- 

 ing amidft the branches of the forcft. Many trees which grow along 

 the banks bend their branches into the water, particularly the mangrove. 

 To thefe the oyfters hang in clufters, like apples on a tree ; and as the 

 weight of the fifh finks the branch into the water, where it ftill continues 

 growing, the number of oyfters increafe, and hang upon it. They 

 are often found to ftick to each other. This is efFeded by means of a 

 glue proper to themfelves, which, when cemented, is as hard as the 

 fhell, and is as difficultly broken. The joining fubftance, however, is 

 not always glue ; but the animal grows to the rocks, fomewhat like the 

 muflel, by threads which take root in the (hell, and not from the body 

 of the fiih. 



Oyfters ufually caft their fpawn in May, which at firft appear like 

 drops of candle-greafe, and ftick to any hard fubftance : thefe are co- 

 vered with a ftiell in two or three days. In three years the animal is 

 large enough to be brought to market, Oyfters prepared in beds are 

 not fo large as rock-oyfters, which are fometimes as broad as a plate, 

 and admired by fom.e as excellent. In the Eaft Indies, fome oyfter fhells 

 are two feet over, and the fifli capable of furnifliing a plentiful meal to 

 eight or ten men ; but no way comparable to ours for flavour. 



Other bivalved fliell-fifti, the cockle, the fcallop, and the razor-ftiell, 

 have other fmall differences in form or manners; but their power of 

 changing place is their greateft difference. The SCALLOP is remarkable 

 for its method of moving on land, or fwimming on the furface of the wa- 

 ter. When deferted by the tide, it makes remarkable efforts to regain 

 the water. Firft gaping widely its Ihells, often an inch, then lliutting 

 them with a jerk, it rifes five or fix inches from the ground. It thus 

 tumbles any how forward repeatedly, till it has attained its journey's end. 

 When in the water it is capable of fupporting itfelf on the furface ; there 

 opening and Ihutting its Ihells, it rumbles over and over, and makes its 

 way with fomiC celerity. 



The PIVOT or RAZOR-SHELL has a very different kind of mo- 

 tion ; having only a power of finking point downward. Its fliells refemble 

 the haft of a razor j and by this form it is better enabled to dive into the 

 foft fand at the bottom. All its motions are confined to finking or rifing, 

 a foot downwards or upwards, in the fand; for it never leaves the fpot 

 where firft it was planted. From time to time it is feen to rife about 

 halfway out of its hole; but, if difturbed, it finks perpendicularly down 

 again. Juft over the place where the razor is buried, is a fmall hole like 



a chim- 



