102 GERM-CELL CYCLE IN ANIMALS 
and the tissues at and dorsal to the root of the 
intestine” (Allen, 1911, p. 32). 
Of the more recent investigations, facts discov- 
ered by Dodds (1910), Rubaschkin (1910, 1912), 
Tschaschkin (1910), von Berenberg-Gossler (1912), 
and Swift (1914) are especially worthy of mention. 
Dodds (1910) found that in the teleost, Lophius, 
the germ cells in the embryos cannot be definitely 
distinguished previous to the appearance in their 
cytoplasm of a body which stains like a plasmosome 
(Fig. 31, A). Germ cells are undoubtedly segregated 
before this period, but they exhibited no characteris- 
tics with the methods employed which rendered them 
distinguishable. Dodds believes that this cyto- 
plasmic body is extruded plasmosome material, 
probably part of one of the two plasmosomes pos- 
sessed by many of the cells at this period. 
Rubaschkin, in 1910, announced the results ob- 
tained with the eggs of the guinea-pig by certain 
methods designed to bring into view the chondrio- 
somes. He shows that the chondriosomes of the 
undifferentiated cells are granular, and that as 
differentiation proceeds, these granules unite to 
form chains and threads (Fig. 31, B). The sex 
cells, however, retain the chondriosomes in their 
primitive granular form, and remain in an undiffer- 
entiated condition situated in the posterior part of 
the embryo among the entoderm cells. Tschaschkin 
(1910), in the same year, came to a similar conclusion 
from studies made with chick embryos. Rubaschkin 
(1912) has also extended his investigations on guinea- 
