On Variations in Chromosomes. 
ßy 
Charles Edward Walker, 
Director of the Research Department, Glasgow Cancer Hospital, Glasgow. 
With 1 Figure in the text. 
The most closely related organisms vary front each other in at least 
a slight degree with regard to many if not all characters, and the most 
superficial of examinations demonstrates the fact that no two cells, even 
though they both form part of a highly chfferentiated organ of an animal 
or plant, are exactly ahke. The observations here described were nnder- 
taken in Order to ascertain whether similar variations occur among chro- 
mosomes. 
The only observations having any bearing upon this point are those 
of T. H. Moxtgojiery, jr. 1 ) and E. B. Wilson 2 ). These show that in 
the Meiotic Phase (process of reduction) there mav be considerable varia- 
tions with regard to the mode of conjugation of chromosomes. Mont- 
gomery has also shown that supernumary chromosomes may be occa- 
sionally present in the cells of the testis of Euchistus. No changes in size 
or shape are recorded. 
Montgomery and Wilson deal with the modified chromosomes 
wh : ch have been described as occurring in the cells of certain animals, 
t) “A study of the chromosomes of the gern cells of Metazoa”. Trans. Amer. 
Phil. Soc. XX." 1901. 
“Chromosomes in the Spermatogenesis of the Hemiptera heteroptera”. Ibid. 
XXI. 1906. 
“On the Dimegalous Sperm and Chromosomal Variation of Euchistus, etc.” 
Archiv für Zellforschung. V. Band. 1. Heft. 1910. 
2 ) “Studies on Chromosomes, I.” Joum. Exp. Zool. Vol. II. 1905. 
Archiv f. Zellforschung. VI. 33 
