22 HISTORY OF THE OYSTER. 



the illegal mouths, which I am informed is the case. 

 About three iu 1000 had the spawn (PI. V. b) exuded 

 between the bronchiae ; some of this spawn was placed 

 in a tube bottle with salt water, and lived forty-eight 

 hours, although part of the time in my pocket. 



" July 11. — Went on board the fishing-smack ' Iris,' 

 the property of Mr. Laban Sweeting, who accompanied 

 me, dredging in the river Crouch with the light dredges, 

 for the purpose of collecting oysters to lay down for 

 the London market in September. Examined an 

 immense number of oysters of all sizes, but found no 

 small ones in spawn, or presenting the appearance of 

 having spawned. Mr. Sweeting is of opinion that they 

 do not spawn until they are three or four years old ; 

 they are considered fit for the London market at four, 

 five, and six years old, according to their growth, 

 which depends upon the feeding. Very few (three) 

 were found which had not parted with then* spawn, 

 out of many basketfuls looked over : there was no 

 appearance of white spawn, as it is called, in any. 

 Among the shells were dredged up quantities of old 

 shells, stones, and other substances, completely 

 sprinkled over with spat (PI. IV. fig. 4), as the spawn 

 is called by the fishermen : the rubbish called ' cultcli,' 

 consisting of dead shells, unsizeable oysters, &c., was 

 returned to the river. 



" The spat resembles the adult oyster in shape, but 

 is very minute: see PI. IV. fig. 1, magnified 500 times." 



