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upon the nature of the disputed bodies within the protoplasm of the 

 blastomeres of Salpa. 



After having examined several hundred blastomeres all showing 

 the intra -protoplasmic bodies under discussion, I have selected a 

 single blastomere to figure and describe, not because there are not 

 many others showing a similar condition, but because this seems suffi- 

 cient to establish the point. The blastomere figured is one of five 

 appearing in a section of an embryo of S. hexagona at that stage of 

 development when the follicular epithelium of one half of the surface 

 of the embryo is most rapidly proliferating, about the stage shown 

 in Brooks' Fig. 2 Plate XI. The arrow indicates the direction of 

 movement of the follicle cells as they wander into the center of the 

 embryo, where, as described by Brooks, many of them degenerate. 

 The figure is carefully drawn with a Seitz i/io immersion objective 

 and a number 8 compensating ocular. 



The large blastomere, B l., has a very large nucleus, iV, and evenly 

 granular protoplasm which does not stain deeply with hematoxylin, 

 borax-carmine, or saifranin. Outside the blastomere is a mass of more 

 coarsely granular and deeply staining protoplasm in which no cell 

 walls can be discerued, but in which appear many nuclei all exactly 

 resembling the nuclei of the follicular epithelium. These have a defi- 

 nite chromatic reticulum with rather small nodal swellings and no 

 nucleolus. 



Within the protoplasm of the blastomere as shown in this one 

 section are seven bodies similar in size to the follicle nuclei just de- 

 scribed, but quite different in appearance. I believe them to be ingested 

 follicle nuclei. They do not stain so deeply as the nuclei outside, 

 though they are much darker than the protoplasm of the blastomeres 

 in which they lie. We do not find in them the clear cut chromatin 

 reticulum with sharp contours such as we see in the follicle nuclei, 

 but in certain of them we do find what appears to be such a chromatic 

 reticulum degenerating, because undergoing digestion. Observe 

 especially the nucleus a. The reticulum is evident and I think no one 

 can doubt that the body is really a nucleus. Compared with follicular 

 nuclei the reticulum is seen to stain less deeply and the fibrils and 

 nodal masses do not have sharp contours. The whole appearance 

 indicates the beginning of desintegratioîi. I believe this nucleus to 

 have been ingested but a short time previous to the killing of the em- 

 bryo. At b and c are nuclei which have gone further in the process 

 of degeneration, the chromatin threads being more diffuse. At d, e^f 

 and g we see a further stage in the same process and at h. J and k we 

 observe within the ingested nuclei an almost evenly granular mass of 



