258 OTTO GLASER. 



Macroscopically, this precipitate appears to be coarsely 

 flocculent. Its color is yellowish-brown. Under the microscope, 

 granules aside, one sees chiefly fibers. These, when dried on a 

 filter, yield thin felt-like sheets which cannot be readily dissolved 

 in either sea-water or fresh. The material is only slightly soluble 

 in acids and alkalis. 



V. 



The solubilities of the precipitated pigment are such that it is 

 very difficult to test the importance of this material in fertili- 

 zation. So far, nothing that would merit particular attention 

 has come to light and the conclusion that properties highly 

 significant in fertilization are absent is reinforced by the eggs of 

 the starfish, the sand-dollar, the oyster, Nereis and Fundulus, 

 none of which, apparently, secrete anything that corresponds 

 at all closely with the Arbacia pigment. However, there is one 

 suggestive fact: after removal of the pigment, the Arbacia 

 exudate, physically, is a less stable system than before. From 

 unmodified exudate nothing free from sea-salts can be precipitated 

 with 95 per cent, alcohol; with the pigment removed, 95 per 

 cent, alcohol, insufficient to precipitate the sea-salts, throws 

 down the sperm-agglutinating material. It appears therefore 

 as though the pigment in some way stabilized the exudate. 



LITERATURE. 

 MacMunn, C. A. 



'85 On the Chromatology of the Blood of Some Invertebrates. Quart. }ourn. 

 Mic. Sci., Vol. 25. 



AMHERST COLLEGE, 

 March i, 1921. 



