SPERMATOGENESIS OF ASCARIS 439 
pears around or within them, I merely say that similar facts have 
been observed in connection with the leucopasts of plants.’ These 
sentences are quoted from the close of the introduction to a very 
complete review of the literature on mitochondria. 
Mitochondria as yolk-forming factors in spermatozoa and in eggs 
In this comprehensive study, Faure-Fremiet shows that this 
material occurs in sex cells under four different types of formation 
and behavior. In the last of these he includes all those cases in 
which the mitochondria transform partially or wholly into yolk. 
The spermatocytes of batrachians and of myriapods, and the 
oocytes of many groups of animals are cited here. 
Prennant (’87), in the spermatocytes of myriapods, observed 
certain granules and filaments which he named ‘ergastoplasm,’ 
because he considered them as active elements in the cell. In 
1905 Bouin showed that these bodies transform into yolk. Meves 
and Korff (’01) call this material ‘mitochondria,’ as its behavior 
in the myriapods was like that of mitochondria in other forms. 
Benda (’03) found the mitochondria in the spermatocyte of 
Rana in a compact mass in a cavity in the nuclear wall. He 
called this mass the ‘corps condriogens.’ Champy (’09) found, 
here and there, in the spermatocytes of Bombinator ‘yolk vesi- 
cles’ of various sizes among the mitochondrial granules and fil- 
aments. They resembled the nucleolus inside the nucleus in 
staining reaction but they are often made of two spheres, the 
inner one always staining lighter or more acidophilic than the 
outer. This author believed that yolk is formed in these ‘cyto- 
plasmic nucleoles’ or mitochondria, just as in the oocytes of 
Bombinator or other forms. 
Very clear cases of the transformation of mitochondria into 
yolk have been found in the developing oocytes of a number of 
animals. The simplest case recorded by Faure-Fremiet is found 
in the chilopods, where there is no yolk nucleus or vitelline body 
of any kind. The mitochondria themselves become yolk gran- 
ules, then vesicles or globules, just as they do in the spermatocytes 
of these forms. 
