1884. ] Recent Literature. 169 
The terminal chamber, in which the egg is formed, consists of 
two parts. The wall of the upper part is formed of pavement 
epithelium, which is continued into the solid interior part. In’ 
the interior of the upper part he finds a rounded mass of proto- 
plasm, and between this and the external layer of pavement epi- 
thelial cells is a single layer of large cells (the ovula). These 
cells are each connected with the internal mass by a pedicel of 
homogeneous protoplasm. The pavement epithelial cells pass 
into long cylindrical cells at the inferior part of the terminal 
chamber ; this part of the terminal chamber contains, as a rule, 
only one large cell, the young egg, which is also connected with 
the central mass of protoplasm by a pedicel. 
In the oviparous Aphis, in which a similar structure of the ter- 
minal chamber is well known, the cells of the upper part of this 
chamber have been generally taken for vitelligenous cells, one 
cell in the lower part for the egg and the pedicel for a passage for 
vitellus prepared by the vitelligenous cells. 
Will shows, however, that at least in the agamic Aphis the ele- 
ments have quite a different signification. He considers the cells 
in the upper to be ovula (eianlagen), and the large cell in the 
lower part a young egg. 
The pedicel has nothing to do with a yolk passage, but only 
corresponds to the pedicels of the ovula. 
€n one of the ovula has reached a certain size it leaves the 
“pper part of the chamber, but the pedicel remains and forms 
later that which the authors have called the yolk pedicel (dotter- 
Strang); this remains until the blastoderm is develo 
We often find as many as three successive eggs in connection with 
the terminal chamber. 
n the way downward the egg continually grows, and the 
Cells of the epithelial covering becoming more and more de- 
Pressed ; the ovula do not increase in size at all. 
Here two very interesting questions arise: (1) Why does one 
of the ovula of the terminal chamber leave its place and become 
pay 4 egg? (2) Why do the eggs and not the ovula increase 
ze 
(1) At the time when no ovulum has yet left the terminal 
oF ail and when all the elements of this part of the ovary are 
eal supply of nourishment from the blood which bathes the 
“terior wall of the chamber. The cells grow equally, and exert 
io Pressure in the wall of the chamber, and the result must 
of a bursting of the wall of the chamber or a protrusion of one 
ber ae into the chamber below. At the base of the cham- 
teed 
€ it passes into the oviduct, the resistance is much less 
