JOURNAL 



OF THE 



WASHINGTON ACADEMY OF SCIENCES 



Vol. VIII APRIL 4, 1918 No. 7 



GEOCHEMISTRY. — Note on the inorganic constituents of two 

 small crustaceans.^ F. W. Clarke and B. Salkover, 

 Geological Survey. 



It is well known that very small crustaceans, such as the 

 copepods, form an important part of the marine plankton, and 

 that they serve as food for larger animals, like the fishes and 

 cetaceans. The larger crustaceans all have shells or skeletons 

 which contain much calcium phosphate, and a comparison of the 

 two classes seemed to be a matter of some interest. Accordingly 

 two samples, each made up of hundreds of individuals, were ob- 

 tained from the U. S. National Museum and subjected to partial 

 analysis. They were as follows: 



1. Temora longicornis (O. F. Miiller), from the coast of New 

 England. Weight of dried sample, 0.6105 gram, A copepod. 



2. Thysanoessa inermis (Kroyer), from Balena, Newfoundland. 

 Weight of dried sample, 1.5973 grams. A small shrimp. 



As the amount of material was insufficient for a thorough 

 analysis, only three determinations were made on each sample. 

 They were: loss on ignition, mainly organic matter and water; 

 phosphoric oxide; and residue insoluble in acid. The phosphoric 

 oxide, P2O5, was recalculated into the form of tricalcic phosphate, 

 Ca3P208, and with that adjustment the analyses assume the fol- 

 lowing shape. 



• Published by permission of the Director of the U. S. Geological Survey. 



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