NOWLIN: CYTOLOGICAL STUDIES OF FEMUR-RUBRUM. 401] 
into broad, faintly staining bands. (Fig. 13.) Finally the 
chromatin forms faint rings (figure 14), and the o6gonia have 
all the appearance of cells in prophase, but instead of con- 
tinuing division, now there follows a long rest and further 
growth stage, in which the nucleus takes the typical germinal- 
vesicle form, and the cytoplasm fills with yolk. 
Many dividing somatic cells are to be found around the 
growing eggs in the follicular tissue. Numerous attempts to 
count the chromosomes were made, and the greatest number 
found was twenty-two. I take this to be incorrect, however, as 
counts on other female cells have given twenty-four. In 
Stenobotherus (McClung 11) there are twenty-two chromo- 
somes in the female, but two of these are multiples. I have 
not been able to identify any multiple in femur-rubrum. 
Wilcox says, on page 9 (795): “I could not determine how 
many divisions the spermatogonia undergo. The chromosomes 
in the prophases are twelve in number, twenty-four at the 
equator of the spindle, during metakinesis. The individual 
chromosomes are rod shape, or often elongate spindle shape. 
In metakinesis they show ordinarily the well-known V-shaped 
figures, and are connected with each other in pairs by means 
of linin fibers.” Whether this writer had confused second 
spermatocyte and spermatogonia I do not know. At any rate, 
his count for spermatogonia is incorrect. And it.is even more 
peculiar that he considered the divided twelve as twenty-four 
chromosomes instead of two newly formed cells, each with 
twelve chromosomes. : 
Spermatocytes. 
The early spermatocytes show faintly staining nuclei, with 
chromatin scattered in loose threads of varying lengths. ‘The 
threads seem irregular in diameter, giving the effect of a 
greater amassing of granules at certain points. (Fig. 16.) 
The threads assume more definite outlines later and become 
finer. They still have the beaded appearance, and at one time 
form a bouquet stage, all looping out of a darkly staining 
chromatin mass at the periphery of the nucleus. (Fig. 17.) 
The beaded appearance is seen just before the spireme breaks 
up (figs. 19, 20), and even in the early chromosomes this 
appearance is retained. Wilcox believed that four of these 
nodules are grouped together to form the tetrad, and thet what 
we know as the tetrad is made up of four chromosomes. He 
