Vol. XXXVII. November, 1919. No. 5. 



BIOLOGICAL BULLETIN 



THE NATURE OF THE FERTILIZATION MEMBRANE 

 OF ASTERIAS AND ARBACIA EGGS. 1 



WALTER E. CARREY. 



It is generally believed that the fertilization membrane of an 

 echinoderm egg is a distinct structure formed by the egg, and 

 separated from it by the liquid rilled perivitelline space. Views 

 quite at variance with this current one have been advanced in 

 recent communications; these we believe are not justified by 

 the experimental evidence which is to be considered below. 



I. Elder, 2 Kite 3 and McClendon 4 have separately maintained 

 that the egg jelly is essential to the formation of the fertilization 

 membrane and in one way or another enters into its composition. 

 Harvey 5 has made this question one of special study and presents 

 convincing experimental evidence to show that the egg jelly is 

 not essential. He was able by repeated shaking and continued 

 washing with sea water, to remove this jelly so completely 

 that not a trace could be detected when the eggs were examined 

 in India ink suspensions. Fertilizations of such eggs caused the 

 formation of fertilization membranes, which however may be 

 more tenuous than normally, probably due to the fact that the 

 jelly facilitates the membrane formation by acting as a mechan- 

 ical block to the diffusion of the membrane forming colloid 

 ("membranogen") which was thus retained in more concentrated 

 solution and consequently formed a denser membrane. 



J. Loeb 6 found that hydrochloric acid would dissolve the jelly 



1 From the Physiological Laboratory of Tulane University, New Orleans, and 

 the Marine Biological Laboratory, Woods Hole. 



2 Elder, Arch. f. Enlwick., 1913, XXXV., 195. 



3 Kite, G. L., Science, 1912, N.S., XXXVI., 562. 



4 McClendon, J. F., Internal. Zeitschr. f. physik. chem. Biol., 1914, I., 163. 

 6 Harvey, E. N., BIOL. BULL., 1914, XXVII., 237. 



6 Loeb, J., Science, 1914, N.S., XL., 318. 



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