140 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



' The relative quantities of iron present in the gills as 

 compared with the rest of the body were next determined 

 in French, Dutch, and American Oysters. Six Oysters, 

 or the gills of six Oysters, were analysed in each case 

 with the following results : — 



Six Oysters. 



Weight of Iron found in 

 mgrme. 



French. 



Dutch. 



American. 



Gills 



Bodies minus gills ... 



0-6 

 1-2 



0-4 

 1-5 



2-3 

 1-7 



Weight of ash of gills 



,, ,, of bodies minus gills 



0-1880 

 05980 



0-0217 

 0-1125 



0-0294 

 0-1240 



% Iron on ash. Gills 



,, „ Bodies minus gills 



32 

 0-20 



1-85 

 1-33 



7-82 

 1-37 



Ratio of Iron in gills to Iron in rest of 



body. 

 Calculated per Oyster .. 



,, on ash ... 



1 : 2 

 1-6 : 1 



1 : 3-75 

 1 : 4-1 



1 :0-74 

 5-7:1 



' From these figures it is evident that the gills of the 

 French Oysters do not contain an excessive quantity of 

 iron such as might account for their colour. Calculated 

 per Oyster the gills contain less iron than the rest of the 

 body, except in the American Oyster ; calculated as a 

 percentage on the ash the reverse is the case. The 

 proportionate quantity of iron in the gills as compared 

 with the rest of the body is somewhat greater in the 

 French Oysters than in the Dutch, but much less than in 

 the American. 



1 Clearly, therefore, there is no connection between the 

 green colour and the quantity of iron present. This result 

 is quite in accord with Eay Lankester's observation that 

 his " marermin " is free from iron as well as from copper. 



' Both the gills and bodies of Oysters contain a small 



