206 MARY T. HARMAN 
cells which divide amitotically are in process of degeneration. 
In a discussion of the question of amitosis Vom Rath (91) states 
that when a cell has once divided amitotically it never again 
divides mitotically. Since 1892 a number of observers have 
recorded the occurrence of amitosis both in the somatic cells 
and the sex cells, but its unquestionable occurrence has been 
shown in few cases. 
In the present paper the division of the sex cells only will 
be considered. Whether the sex cells or their progenitors ever 
divide amitotically is a question of interest on account of its 
bearing on a number of theories, among which are those of hered- 
ity, the continuity of chromosomes, and the reiation of the sex 
chromosomes to the determination of sex. A number of observ- 
ers have described amitotic division in both the testes and the 
ovaries of many animals. Meves (’94) describes the spermat- 
ogonial cells of Salamandra as dividing amitotically in the 
autumn and mitotically in the spring. However, his descrip- 
tion of amitosis is very different from the process as usually de- 
scribed. He describes and figures the nucleus as being divided 
by the apparent constricting power of a ring-shaped centrosphere. 
Preusse (’95) describes the appearance of amitosis in the ovaries 
of Hemiptera. Gross (’01) also finds amitosis in the ovaries 
of Hemiptera, but he contends that those cells which divide 
amitotically are degenerating or are secretory cells and there- 
fore do not give rise to ova.. Amitosis is recorded as occurring 
in the spermatogonial cells of Amphiuma by- McGregor (’99). 
He says: ‘‘Amitosis occurs among primary spermatogonia and 
is, apparently, a normal process. Secondary spermatogonia 
divide only by mitosis and contain the somatic number of 
chromosomes.” 
In 1904 Child gave a brief account of the occurrence of a mito- 
sis in Moniezia in the early stages of segmentation. In a series 
of papers (’07) he described amitosis as taking place in the devel- 
opment of the reproductive organs, in the spermatogonial divi- 
sions, in the oogonial divisions, and in later segmentations. He 
also finds mitoses in all these places except in the later segmenta- 
