Amitosis in the Ovary of Protenor belfragei and a Study of the Chromatin Xucleolus. 219 
cyte groups. In photo 36, plate XVI the pair of chromosomes next in size 
to the largest are together nearly if not quite eqnal in size to the largest. 
chromosome but in the spermatocyte group from the same testis shown 
in photo 43 the chromosome on the upper periphery of the group w hielt 
must represent the large chromosome of the spermatogonial group is 
not as large as the largest tetrad, in fact it is more nearly the size of 
the second tetrad. 
Such irregularities in the form and size of the chromosomes are in- 
consistent with the theories which attribute so much value to these 
relations that they are supposed to regulate certain vital phenomena, 
even so fundamental a phenomenon as the determination of sex. Such 
irregularities Support rather the conclusions of those who hesitate to 
attribute so much significance to the morphology of the chromo- 
somes. 
Such an experienced cytologist as Prof. Farmer concludes that the 
facts “force a surrender of the doctrine that there exists any permanent 
structural arrangement in an individual chromosome lasting from one 
generation to another . . . The chromosomes like other Organs are 
subject to change both as to size and number. Such a difference is not 
uncommon between closely allied species and in several of the ferns to 
which I have referred the number is not constant even in the same indi- 
vidual. It would seem, then, that the bodies in question form rather 
a frail support for the heavy weight of speculation that has been piled 
upon them” p. 462. 
Professor Farmer is one of several investigators who has recognized 
a Variation in the number of chromosomes even in the same individual. 
Della Valle (1909) has recently demonstrated in Salamander marked 
variability in the number of chromosomes in the same individual and he 
has exhaustively summed up the evidence pointing to a variability in 
the number of chromosomes in other fonns, claiming that these facts 
are fatal to the continuity hypothesis. 
In a recent paper Winiwarter and Sainmont (1909) have shown 
some degree of inconstancy in the number of somatic chromosomes, but 
what is more important they find the reduced number of chromosomes 
much less than half the somatic number, p. 197: “Une constatation plus 
importante c’est que, chez le cliat comme chez le lapin (von Winiwarter 
1900), le nombre somatique et ovogonial ne correspond pas ä celui de 
l’oeuf ä maturite. Chez le lapin, nous comptions 42 chromosomes d’une 
part et seulement 10 ä 12 (soit 20 ä 24) chromosomes dans la premiere 
figure polaire. Cette remarque, passee inaper^ue dans la litterature, 
15* 
