792 THOS. H. MONTGOMERY, JR. 
that the body cells become different from the germ cells by a 
mechanical process of chromatin diminution, as in Ascaris. 
But this is quite conformable to our argument, for in Ascaris 
those cells which become body cells are the ones that include the 
cast-off chromosome ends in their cytoplasm, and it will prob- 
ably be found that these ejected chromosome parts engender 
such cytoplasmic differentiations as characterize the body cells. 
Either this mechanism of the segregation of the germ cells may 
be admitted, or else one that would cause the mitochondria 
of prospective germ cells to remain unaltered or latent. For- 
tunately this is a matter that may be tested by observation. 
For if the first supposition be correct we should find that during 
cleavage an unequal distribution of the mitochondria occurs, 
just as we know occurs in the case of yolk granules. If the 
second be correct, then while the mitochondria are undergoing 
developmental changes in some of the cells, they should be found 
to remain relatively unaltered in others—the prospective germ 
cells. 
LITERATURE CITED 
BauMGARTNER, W. J. 1902 Spermatid transformations in Gryllus assimilis, 
etc. Kansas Univ. Sci. Bull. vol. 1. 
Benpba, C. 1891 Neue Mitteilungen iiber die Entwickelung der Genitaldriisen 
und iiber die Metamorphose der Samenzellen. Arch. Anat. Phys. 
1898 Ueber die Spermatogenese der Vertebraten und héheren Everte- 
braten. Verh. Physiol. Ges. Berlin. 
1903 Die Mitochondria. Ergebn. Anat. Entw., Bd. 12. 
Bereus, J. 1904 La formation des chromosomes héterotypiques dans la sporo- 
bd genése végétale. 1. La Cellule, tome 21. 
Briackman, M. W. 1903 The spermatogenesis of the myriapods. II. Biol. Bull., 
vol. 5. 
1905a The spermatogenesis of the myriapods. III. Bull. Mus. Comp. 
Zool., Harvard, vol. 48. 
1905b The spermatogenesis of the myriapods. IV. Proc. Amer. Acad. 
Arts and Sci., vol. 41. 
1907 The spermatogenesis of the myriapods. V. Ibid. vol. 42. 
BonnEvig, K. 1906 Untersuchungen tiber Keimzellen. I. Jena. Zeit. Bd. 41. 
1908 Chromosomenstudien. 11. Arch. Zellforsch. Bd. 2. 
