506 ROBERT W. HEGNER 
may still be determined, because of the presence of deeply stain- 
ing rings between the cells (figs. 7-12). 
4. The causes of differentiation could not be definitely de- 
termined, but several hypotheses are mentioned (p. 500). 
5. Granules appear near the nucleus of oocytes shortly after 
their differentiation. Later they become distributed through- 
out the egg cytoplasm. These granules appear to be mito- 
chondrial in nature and to arise from, or under the influence of 
the nucleus. 
II. THE BACTERIA-LIKE RODS AND SECONDARY NUCLEI IN THE 
OOCYTES OF CAMPONOTUS HERCULEANUS VAR. 
PENNSYLVANICA DEG. 
The important contributions by Blochmann (’84, ’86) upon 
the growth of the oocytes in ants seem to be the only reports 
that have ever been made on this subject. Blochmann dis- 
covered two very interesting facts regarding these oocytes: (1) 
the presence of rod-shaped bodies almost completely: filling the 
growing egg which he considered symbiotic bacteria, and (2) 
the formation of nuclear-like bodies around the oocyte nucleus. 
Recently Tanquary (’13) has described, in the freshly laid eggs 
of the carpenter ant, a body which he calls a cleavage nucleus, 
but which resembles very closely bodies that have been dis- 
covered in the eggs of other animals and to which I have applied 
the term keimbahn- or germ-line determinants. The obser- 
vations recorded in the following pages were made in order to 
trace the genesis of the eggs of ants with special reference to the 
origin, distribution, and fate of the bacteria-like bodies, nuclear- 
like bodies, and the germ-line determinants. 
The material used for these studies consisted of the ovaries 
of the carpenter ant, Camponotus herculeanus var. pennsyl- 
vanica DeGeer. A large number of virgin queens were obtained 
from a dying apple tree on April 3, 1914, and some of them were 
kept alive until June 9, 1914. The ovaries were dissected out 
in Ringer’s solution and immediately fixed in the same manner 
as were those of the honey bee (page 496). Ovaries were pre- 
served at intervals of a few days during the period of two 
