a FOOT. [Vou. XII. 
The method that has proved most satisfactory for eggs of 
Allolobophora foetida is to stain the sections from one to 
twenty-four hours in lithium carmine, wash in acidulated 
alcohol for a few seconds, and double stain with a very dilute 
solution of Lyon’s blue. The length of time required for 
staining depends upon the fixative used. The process must 
be carefully watched under the microscope; for the lithium 
carmine in both the spindle fibres and cytoplasmic network 
may be replaced by the Lyon’s blue.’ If the staining be 
properly modified to suit the special fixative, all the fixatives 
tested give results more or less satisfactory; but corrosive 
sublimate, with or without acetic acid, gives the most brilliant 
and satisfactory reaction. A more detailed description of the 
effect of the various fixatives upon the polar ring substance 
will be given later. 
Before describing the figures, I would emphasize the fact 
that each is an exact representation of the preparation both in 
form and color, most of the work having been done by an 
expert draftsman and colorist (Mr. H. Bridgham) ; not even 
in shade or tint is there any variation from the original. 
None of the figures are in the least diagrammatic; they were 
drawn from sections, the camera lucida being used in all cases. 
Each egg (taken from a cocoon) was studied under a Zeiss 
2mm. immersion lens, and drawn with the aid of an Abbe 
camera, before it was imbedded for sectioning.2 The varia- 
tions in size of eggs of nearly the same stages of develop- 
ment are largely due to unequal shrinkage, dependent upon 
the fixative used. 
Fig. I represents a very young oécyte. In the cytoplasm, 
in close contact with the nucleus and sharply differentiated 
from the chromatin, nucleolus, and cytoplasm, is a_ blue, 
granular mass,—the so-called yolk-nucleus. This substance 
1 If the odgonial areas are overstained with Lyon’s blue, the nuclei appear im- 
bedded in a matrix of blue; the cell boundaries, red cytoplasm, and capillaries 
being obliterated. If preparations fixed by Hermann’s fluid are overstained, the 
nucleoli as well as the yolk-nucleus will stain blue. 
* These facts are emphasized in order to prevent a mistake similar to the one 
made regarding the figures of my preliminary note. The American Naturalist, 
vol. XXIX, January, 1895, speaks of my “ diagrammatic figures.” 
