468 



Transactions of the Society. 



membrane is to be regarded as a sort of skin enclosing the nucleus, 

 or, in other words, that it is a continuous sheet. But on looking 

 at the sections in which a portion of the nucleus has been shaved 

 off, instead of a continuous outline around the opening, the contour 

 seen is broken, and consists merely of a series of granules of 



Fig. 66. — Nuclei from growing root-tip of Allium, Fritillaria, 

 and Hyacinthus. 



chromatin with an occasional connecting thread of linin, some of 

 the chromatin granules being irregular in shape and elongated, so 

 as to give the appearance of a well-defined edge in parts only of the 

 contour of the aperture. When a complete nucleus is observed, the 

 erroneous appearance of a limiting nuclear membrane is produced 



Fig. 67. — Nuclei : Testis of Salamander and Triton. 



on account of the fact that both the reticulum of the cytoplasm and 

 also that of the linin of the nucleus with its chromomeres are so 

 closely associated (see Plate XXI, figs. 5 and 6), and take stain 

 in a manner that, when the outline of the nucleus is looked at, we 

 are regarding the side of the nucleus tangentially, increasing the 

 depth of colour and enhancing the false appearance of a nuclear 

 coating. Accordingly, the nucleus is evidently not surrounded by 



