CYTOLOGY OF ANISOLABIS MARITIMA BON. 
239 
ures 1-4 (Plate XXIV) represent four typical metaphase plates. 
Subsequent observations lead the author to believe that, of the 
twenty-six chromosomes, twenty-two are autosomes, and four 
are two double x-chromosomes, which appear in quiescent 
oogonial nuclei as two double and almost square karyosomes. 
The female somatic number has likewise been established 
to be 26. The counts were made on well-developed embryos, 
treated by the same methods as the gonads. Numerous mitoses 
in the hypodermal cells and in the developing central nervous 
system offered abundant material for statisfactory counts. A 
suitable embryo would be selected and then sketches made of 
every distinct metaphase plate in the whole series of sections. 
Figures 5-8 (Plate XXIV) represent four groups showing 26 
chromosomes each. These are selected from a single embryo in 
which dozens of clear counts of 26 were made. In the somatic 
cells, as has been noted by previous investigators, there is a 
much greater variation in the size of the cells and the form of the 
chromosomes (whether long and narrow, or short and broad) than 
there is in the germ cells. The chromosome number, however, 
remains constant, with the occasional exception of a giant cell 
with twice the diploid number present. 
B. The male 
Spermatogonia likewise have clear, clean-cut chromosomes, 
twenty-five in number, cells near the apex of the tubule serving 
best for such counts. These spermatogonia have a large amount 
of cytoplasm and the chromosomes are well separated (Plate 
XXIV, figs. 9-12). In the cytoplasm onemay often encounter 
bodies, which might be mistaken for chromosomes in deeply 
stained haematoxylin preparations, especially after Bouin or sub- 
limate fixation. In such preparations these cytoplasmic masses 
are quite as dark in color as the chromosomes and not greatly dif- 
ferent in size from the average Anisolabis chromosome. These 
bodies are shown, light gray in tone, in figures' 9, 11, and 12 of 
Plate XXIV. After Benda fixation these cytoplasmic bodies take 
mitochondrial stains, and stand out in marked contrast to the 
