478 HOPE HIBBARD 



after ordinary Bouin fixation. The shape and distribution of 

 mitochondria in the eggs of Echinarachnius are shown in figures 



13 to 17 which were drawn from a series of eggs fixed in modified 

 Bouin and stained in Benda's alizarin and crystal violet, and in 

 figures 4, 5, and 6 which were drawn from a series fixed in Flem- 

 ming without acetic followed by the Benda stain. 



The study of this material indicates that the mitochondria 

 bear a definite relation to the fine uniform fat droplets described 

 above. In figure 4 there is shown an unfertilized egg fixed in 

 Flemming without acetic and stained according to Benda's 

 method in which the mitochondria were deep violet. They are 

 shown as black granules in the figure. The egg also contains 

 granules which appear the same in size, shape, and distribution 

 but which take the violet stain with varying degrees of intensity 

 or which may be quite pink like the ground cytoplasm. There 

 is also a continuous variation in color from the small fat droplets 

 which are brown from osmic-acid impregnation, through similar 

 granules which are less and less brown, to pink granules. It seems 

 probable, therefore, that the small fat droplets which are formed 

 by emulsification of larger fat drops change gradually, as indicated 

 by differential staining, into the bodies which take a deep violet 

 stain after Benda's method and are identified as mitochondria. 



In the modified Bouin material, the mitochondria are stained 

 a deep violet with the Benda stain. They are the granules illus- 

 trated in figures 13 to 17. These same eggs when stained with 

 iron hematoxylin show many more black granules than can be 

 identified as mitochondria. Figure 18 shows such an egg thirty 

 minutes after insemination which contains a larger number of 

 black granules than the number of mitochondria shown in figures 



14 and 15. No granules stain with sudan III after this fixation. 

 The relation between the mitochondria and the nutritive plates 



may be considered here. The great mass of plates is already 

 formed by the time the egg is ripe, but there is some indication 

 of how they may be formed. In the eggs from which figures 4, 

 5, and 6 were drawn the mitochondria were stained violet and the 

 nutritive plates pink. In figure 4 and more especially in figures 

 5 and 6 some of the mitochondria show pale centers. In fact, 



