โ Scribed by Leitch, James L.
No coin nor oath required. For personal study only.
In a previous publication, Leitch ( '31), the permeability of the eggs of six species of Pacific Coast invertebrates was calculated on the assumption that 15 per cent of the volume of the eggs is osmotically inactive. This is the value found from swelling experiments by McCutcheon, Luck&, and Hartline ( '31) for the eggs of the sea urchin, Arbacia punctulata. Inspection of table 1 and column 6 of table 2 of Leitch ('31) shows that this correction does not make the permeability constants independent of the concentration of the external solution, although it does so in the case of Arbacia. This suggests that either the assumed non-solvent volume was incorrect for these species o r that other factors, not operating in the case of Arbacia eggs, must be considered. The present paper gives the results of a study of the non-solvent volumes of four of the Pacific Coast forms as determined by swelling experiments and by chemical analyses of the eggs.
The materials from which the data for this paper were obtained were the eggs of the starfish, Pisaster ochraceus, of the two sea urchins, Strongylocentrotus franciscanus and S. purpuratus, and of the estuarine worm, Urechis caupo.
The methods of obtaining eggs of these species were the same as those already described (Leitch, '31).
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