EGG SECRETIONS OF ARBACIA AND ASTERIAS 497 



A consideration of the above facts makes it seem probable 

 that the factors tending to produce development in the resting 

 egg are of the nature of enzymes. The action of these, Jobling 

 found, may be inhibited by unsaturated fatty acids. The 

 egg remains in the resting stage so long as the action of these 

 enzymes is inhibited by the unsaturated fatty acid. The egg 

 itself, when mature and in a suitable medium, produces a lipolysin 

 which binds this inhibitor. The efficiency of the inhibitor may 

 also be lowered by physical and chemical means. In some groups, 

 the spermatozoon appears to bind the inhibitor, in others, to 

 increase the activity of the enzymes. 



V. LITERATURE CITED 



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 and after fertilization, with especial reference to the relation of cata- 

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EuLER, H. 1912 General chemistry of the enzymes. J. Wiley & Sons, New- 

 York. 



FucHS, H. M. 1914 Studies in the physiology of fertilization. II. The action 

 of egg secretions on the fertilizing power of sperm. Archiv f. Entw'- 

 mech. d. Organismen, Bd. 40, pp. 205-252. 



Glaser, O. C. 1913 On inducing development in the sea-urchin (Arbacia 

 punctulata), together with considerations on the initiatory effect of 

 fertilization. Science, N. S., vol. 38, pp. 446-450. 



1914 a The change in volume of Arbacia and Asterias eggs at fertiliza- 

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1914 b A qualitative analysis of the egg-secretions and extracts of 

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1914 c On auto-parthenogenesis in Arbacia and Asterias. Biol. Bull., 

 vol. 26, pp. 387-409. 



Godlewski, E. 1911 Studien iiber die Entwicklungserregung. II. Antagon- 



ismus der Elinwirkung des Spermas von verscheidenen Tierklassen. 



Archiv f. Entw'mech. der Organizmen, Bd. 33, pp. 233-254. 

 Jobling, J. W., and W. Petersen. 1914 a Soaps as ferment-inhibiting agents. 



Jour. Exp. Med., vol. 19, pp. 239-250. 



1914b Nature of serum anti-trypsin. Jour. Exp. Med., vol. 19, pp. 



459-478. 

 Just, E. E. 1915 a Initiation of development in Nereis. Biol. Bull., vol. 28, 



pp. 1-17. 



1915 b An experimental analysis of fertilization in I'latynereis mega- 

 lops. Biol. Bull., vol. 28, pp. 93-114. 



