ELECTROLYTE CONTENT OF SEA URCHIN EGG. 17 1 



250,000 eggs were analyzed, the results are calculated to a basis 

 of 404,000 eggs for comparative purposes. At least two analyses 

 were done for each element determined but the results are 

 statistically not so accurate as the Arbacia analyses due to the 

 relatively small number of estimations. The relative values are 

 probably more accurate than the absolute. 



TABLE II. 



ELECTROLYTE CONTENT OF THE Asterias EGG. 



Mgs. per 

 Radical. 404.000 Egg?. 



Calcium 1.487 



Magnesium 2.101 



Sodium 4.84-7.27 



Potassium 6.77 



Lipoid phosphorus O-54I 



Acid soluble phosphorus 0.591 



Due to the incompleteness of the data in Table II the milli- 

 equivalents are not calculated. 



DISCUSSION. 



In both the star fish and sea urchin egg the potassium is 

 higher than the sodium although in the sea water of Woods Hole 

 the sodium is much higher than the potassium. (See page (8) for 

 analysis of Woods Hole sea water.) The Ca : Mg in the sea 

 urchin egg is approximately I : 2 and in the star fish egg the Mg 

 in the ratio is slightly lower than 2. Total phosphorus is slightly 

 higher in the star fish than sea urchin but the distribution is 

 about the same between lipoid and acid soluble. (See also 

 page (7).) Sulphate in the sea urchin is very low. 



Using the salicylic acid method for iron determination the 

 values found for Arbacia punctulata are higher than those found 

 by Warburg (9) for Stropgylocentrotus lividns. We find 0.24 

 mgs. per gram of dried eggs whereas his value is only o.oi mg. per 

 gram. 



The fact that the cation equivalent is much higher than the 

 anion opens an interesting field for speculation. Presumably 

 much of this excess cation is combined in the lipoid phase and 

 some held by proteins. Certainly much of it must be osmotically 

 inactive. 



