2 LOOT. [ VoL. UT: 
In the following winter, the ovarian egg of Lumbricus was 
studied by Mr. Calkins! in the laboratory of Professor E. B. 
Wilson of Columbia College. His results differ so radically 
from those obtained by the study of AJ/olobophora foetida 
that I think it best to give a brief account of my results. 
Calkins’s results are, briefly, as follows: ‘‘ The yolk-nucleus is 
chromatin in the form of granules.’”’ ‘This granular mass 
disintegrates and the parts form the yolk plates of the egg.”’ 
In Allolobophora foetida the “yolk-nucleus”’ can be sharply 
differentiated from the chromatin, and in normal eggs I find 
no structures answering to the “great yolk plates’’ described 
and figured by Calkins for Lumbricus. In a few cases, how- 

Fic. 1.— Section of a degenerating egg from Fic. 2.— Calkins’s Fig. 5 reduced 
ovary of All. foe. Abbe camera. one-half. 
ever, in ovaries from worms past the breeding season (clitellar 
region no longer marked), I find, among eggs in various stages 
of degeneration, some that exactly correspond to Calkins’s 
figure 5 ; the chromatin has for the most part lost its granular 
structure, forming one or more solid homogeneous masses 
among the granules, and in the cytoplasm there are large 
homogeneous masses, which appear to be identical with 
Calkins’s “grezt yolk plates.” 
Ovaries from worms without a defined clitellum show various 
stages of degeneration. In some cases the eggs of one ovary 
will be entirely degenerated, while those of the other will 
appear normal; again, only the older eggs of one or both 
ovaries will show degeneration; while in some cases both 
1 Gary N. Calkins, ‘Observations on the Yolk-nucleus in the Egg of Lumérz- 
cus.” Transactions New York Acad. of Sci., June, 1895. 
