No. I.] SPERMATOGENESIS OF BATRACHOSEPS. 35 



As regards the nature of the shell of darker granules surround- 

 ing the linoplasts, I have not any observations. This shell 

 seems to exist only during the resting stages of the polymor- 

 phous nuclei and not in the maturation cells. Besides pure 

 linin granules the linoplast undoubtedly also contains secretions 

 with which the linin is nourished. The function of the lino- 

 plast appears thus to be not only to furnish stored-up linin, but 

 also to nourish the general linin network. I hardly need to 

 point out that the linoplast has been variously termed paranu- 

 clein, pyrenin, true nucleoli, Kernkorperchen, etc. 



Linin. — The linin network is not difficult to differentiate, 

 as with the congo-iron-haematoxylin method it stains reddish- 

 yellow, while nearly all other structures take a black or at 

 least a gray stain. When insufficiently differentiated it some- 

 times appears as if the chromatin of the chromosomes extends 

 far out into the linin network ; and in this way it is generally 

 figured. With proper differentiation, however, it is seen that 

 this is not the case, but that the chromatin is never extended 

 into the linin, at least never as a fine thread (Figs. 14, 24, 

 119, etc.). As long as the nuclear membrane is unimpaired 

 the linin always has the appearance of fine network, com- 

 posed of granules of equal size and form. These granules 

 occur either singly or in small groups, which latter may be 

 mistaken for larger granular units. In Figs. 14 c and 26 b \ 

 have figured these granula in the way they appear under the 

 most favorable optical conditions, though the individual gran- 

 ules are perhaps somewhat more rounded than they appear in 

 the illustrations. We must distinguish between two distinct 

 periods in the life cycle of the linin, one being the periods of 

 rest, the other the periods of activity. There are two periods 

 of rest. One is found in the resting stage of the nucleus 

 before the leaders have properly formed, and the other occurs 

 later in those stages of mitosis in which the nuclear membrane 

 has been dissolved, and the linin been scattered away from the 

 chromosomes. In the former of these stages the linin gran- 

 ula are more regular than in the latter (Figs. 1-3, etc., also 

 Figs. 26, 37). After the nuclear membrane has been dissolved 

 the linin network is carried away from the chromosomes, and 



