126 



THE AMERICAN ARBACIA 



empty in the living egg, stains blue and consists of very small granules, 

 the microsomes; this was described in the early paper of Lyon (1907). 

 The yolk stains orange with a rose tinge and the pigment orange. The 

 mitochondria can sometimes be distinguished as a darker bluish band 

 between the protoplasm and the yolk. The oil cap does not show; it is 

 probably dissolved in the fixing fluid. The two half-eggs show the 

 same stratification except that one usually sees a blue cap of proto- 

 plasm on the red half-egg, especially when well centrifuged so as to 



TABLE 8 



VITAL DYES ON CENTRIFUGED UNFERTILIZED EGGS OF ARBACIA PUNCTULATA 



(From E. B. Harvey, 1941 c, with a few additions) 



Toluidin blue Pinkish 



lavender 



o Pinkish 

 lavender 



Lavender Lavender 



Purple to 

 blue black 



More intense 

 if stained 

 after cen trif. 



