224 CELAPPOLE. [VoL. XIV. 
some of the characteristics of the true ovum, and are ova that 
have passed in the course of development up to a certain point. 
The nuclei must then have undergone a degenerative hyper- 
trophy, as they are much larger than those-of the developing 
ovum of the corresponding stage. The cell body grows smaller 
and takes the Lyon’s blue stain strongly on double staining 
after lithium carmine. The ultimate fate of these cells is the 
same as that of the nutritive cells, — degeneration and ab- 
sorption. 
The last stage in which the nucleus of the ovum is recogniz- 
able is shown in Fig. 4. The egg now consists of an irregular 
vesicular mass of protoplasm which forms the cell body in 
which a very small nucleus or germinal vesicle is eccentrically 
placed. This nucleus is irregular in outline with very small, 
peripherally arranged chromosomes, the number of which it was 
impossible to determine exactly; by inference it would be eight. 
The germinal vesicle has every appearance of losing its nuclear 
membrane; if this is the case, its apparent disappearance after 
this stage is attributable to the difficulty of distinguishing the 
separated minute chromosomes. In confirmation of this point a 
few observations were made on another apterygote, a thysanu- 
ran (Zomoceras sp.?), in which eggs were found in a similar 
stage as well assomea little moreadvanced. The cells are much 
larger in these animals and the ova are distinctly large masses 
of vesicular protoplasm with a small group of eight chromo- 
somes eccentrically placed, not surrounded by any nuclear 
membrane (Fig. 14, g.v.). 
In the next stage in Anurida, as shown in Fig. 10, the 
nucleus is no longer visible, the protoplasm has increased in 
quantity, and has also become more vesicular. In some of the 
spaces of the network yolk has already begun to appear, as is 
shown by the deep staining of parts in Lyon’s blue. The 
nutritive cells have grown in size and the stellate structure of 
the chromatin is clearly defined. That these stellate masses 
are the chromosomes is shown by the use of the Biondi-Erlich 
stain. In this the stellate masses appear dark green, almost 
black at the central, more dense spot, and lighter green in the 
radiating strands; the non-stellate masses take the bright red 
