ON GREEN OYSTERS. 73 
are accordingly in demand. The preference for green Oysters 
can be traced back as far as the year 1713, when it is recorded 
that green Oysters were served at a supper given by a certain 
ambassador at the Hague. 
In this country green Oysters appear never to have been in 
fashion. They occur in some of the estuaries in Essex, but 
are never sent into the English market; the proprietors always 
export them. I have been enabled by the kindness of a gen- 
tleman connected with the Whitstable oyster trade to examine 
some of these English green Oysters, and I am ina position to 
state that they do not differ from the French ‘“ Marennes”’ 
except in being less strongly coloured than the latter, 
I have not been able to find any record of green oysters 
differing in appearance from that figured in Plate VII. The 
colour is always confined to the gills and labial ten- 
tacles. It may be paler than that of the full-coloured specimen 
figured, but no general green coloration of an Oyster or of 
the Oysters from a particular bed has been recorded. This fact 
will be seen subsequently to have an important bearing on the 
question as to how the green colour is produced. 
The green Oysters of Marennes do not differ in flavour from 
Oysters of the ordinary colour which are brought from the same 
locality, and there is, in the opinion of those who have made 
the comparison (among whom I may reckon myself), no reason, 
from a gustatory point of view, to prefer the one to the other. 
So long ago as the year 1820 the following facts with regard 
to the natural history of green Oysters were made known by 
M. Benjamin Gaillon in the ‘Journal de Physique,’ tome xci, 
p- 222. Iam indebted to an article by the late Mr. Arthur 
O’Shaughnessy (‘ Ann. and Mag. Nat. Hist.,’ vol. xviii, 1866) 
for an account of M. Gaillon’s observations, as well as for other 
references to the history of the subject. 
Green Oysters do not occur in the sea. The green colour is 
acquired only in certain “parks” or reservoirs of salt water, 
where the Oysters are placed by the oyster merchants for the 
purpose of fattening and “greening.” These “parks” are 
about 4 feet in depth and 200 feet in length by 50 feet in 
