YVm. S. Marshall 
(532 
division becomes apparent. The chromosomes duriug division are 
quite large, connecting fibres not very distinct and centrosomes were 
never seen. Neither at this nor at any other stage in tlie growtb of 
the chambers do we find tlie epithelial cells showing any tendency 
to divide in any particnlar direction but the axis of division mav be 
parallel, oblique or transverse to the longitudinal axis of the cell 
(Figs. 11, 13 & 17). 
When the epithelial cells have attained a somewliat larger size 
than those we have just been describing secretorv activity becomes 
quite noticeable (Fig. 10). The oöcyte in such a chamber shows a 
similarity in contents throughout, this is of a finely granulär con- 
sistencv; as yet no yolk globules have been formed. The granulär 
structure of the peripheral layer of the oöcyte is very similar, micro- 
scopically, to the outer margin of the epithelial cells agreeing very 
closely with what Korschelt (15) has said; „als wenn sich das Plasma 
der Follikelzellen an seinem Rande in feine Körnchen auflöse.“ 
Brandt (3) found very similar conditions to what exists in the walk- 
iug-stick. His view can be shown by a quotation: „An einigen 
lebenden, teils erwärmten Präparaten erschien nämlich an optischen 
Durchschnitten nicht selten die Grenze zwischen dem Epithel und dem 
Dotter gleichsam verwischt, indem die Enden der Epithelzellen sich 
in körnige, in die Dottersubstanz verlierende Fasern auflösten. Hier- 
auf basierte ich den Schluß, daß die Dottermasse durch ein Ab- 
tröpfeln von Körnchen von den Epithelzelleu vergrößert werde, also 
durch eine excretorisclie Tätigkeit.“ The figure shown (10) is from 
a chamber with oöcyte 0,39 mm long and the epithelial cell nuclei 
of an average lenght of 0,02 mm. In these cells it is at once noti- 
ced that the cytoplasm lying between the free end of the cell and 
its nucleus contains a number of very large vacuoles; in section seldom 
more than three of these are seen in any one cell but tbey are often 
so regulär as to form a vacuolated margin along the surface of the 
cells. Gross 9) found vacuoles in the epithelial cells of the ovary 
of S/lpha obscura but these were scattercd throughout the cell; he 
attributes them to the rapidity with which the nourishment was passed 
from epithelial cells to oöcyte. The cytoplasm seen between the va- 
cuoles or found in other parts of the cell showed, as has been ob- 
served by others, a great similarity to the peripheral layer of the 
oöcyte i. e. that part of it lying adjacent to the cells. Cell boundaries 
were generally diffieult to trace throughout their entire length, Gross 
(10). This was also true of the boundaries lying along the surfact 
