92 



Papers from the Department of Marine Biology. 



any precipitate filtered off, and the zinc reprecipitated with Na 2 COs 

 and again weighed as ZnO. 



Iron was estimated in a separate sample, usually 2 grams, by titra- 

 tion with permanganate. Manganese was also estimated in a separate 

 sample, by the colorimetric method, and both, as tabulated below, are 

 calculated to amounts contained in 20 grams of the dry sample. The 

 weights, etc., are given in grams. 



'Blood. 



2 Liver. 



