52 CALIFORNIA ACADEMY OF SCIENCES. [jd See., 



cells we must expect to find the same general cytoplasmic 

 characters. While the leucocytes have received much at- 

 tention from a host of investigators, the finer structure of the 

 erythrocytes has hardly been touched upon. This is greatly 

 due to the interference of the haemoglobin, which does not 

 permit the ready staining of the cytoplasm in any way that 

 would permit a study of the finer details. Heidenhain's 

 fig. 16 ("Neue Untersuchungen") demonstrates this. We 

 see polar projections resembling plasmocytoblasts at each 

 end of the nucleus, faintly visible at the upper end, a little 

 more sharply defined below. The two centrosomes at one 

 pole are strongly brought out, but the respective spheres are 

 not to be seen. 



Adolf Dehler, who has made a careful study of the centro- 

 somes of the chicken erythroblasts, gives us as little informa- 

 tion on this particular subject as does Heidenhain. His figures 

 show only sharply defined centrosomes surrounded by a 

 light colored circular sphere. MacCallum's figures show 

 few if any exact details, except the mere outlines of the 

 frayed plasmosphere. E. J. Claypole gives no details of 

 any kind. In our comparisons we must, therefore, turn to 

 other cells, among which there are few which have been 

 more carefully studied than have the giant cells from the 

 bone marrow of the rabbit by M. Heidenhain; and, as re- 

 gards the cytoplasmic parts they show several points of 

 similarity to our plasmocytes and plasmocytoblasts, we will 

 consider them more particularly. 



The concentric arrangement of the cytoplasm, so forcibly 

 pointed out by Heidenhain and Lenhossek, is equally dis- 

 tinct in our plasmocytes. As is known, Heidenhain recog- 

 nizes three distinct zones of ectoplasm, and, similarly, three 

 distinct zones are found in the ectoplasm of the plasmo- 

 cyte. How far Heidenhain's outer, inner, and middle lay- 

 ers correspond with the three outer spheres of the plasmo- 

 cyte is more difficult to determine. 



Judging from the form, situation, and staining quality, I 

 believe it safe to identify the outer zone of Heidenhain's 

 ectoplasm with my plasmosphere. The identity of my hya- 



