224 KANSAS UNIVERSITY SCIENCE BULLETIN. 



of no other value, it would certainly be worthy of study for the 

 light it throws upon the question of the individuality of the 

 chromosomes. On this point Montgomery has much to say in 

 his late paper (15). I think it cannot be questioned that we 

 have here indisputable proof that at least one chromosome may 

 be identified through all the cell generations of the testis. 

 While this does not prove that chromosomes are persisting and 

 independent structures, it does evidence the fact that they may 

 be, and greatly strengthens the hypothesis that they are. 



In addition to the evidence here offered by the accessory 

 chromosome, there must be noted that derived from a study of 

 spermatocytes in which there is always present one ordinary 

 chromosome that greatly exceeds the others in size. Such a 

 condition is found in the cells of Anabrus. The disproportion 

 in size of the elements is here so striking that it would be im- 

 possible to fail in distinguishing the giant chromosome. In each 

 of the spermatocytes of Anabrus there are therefore two chro- 

 mosomes which are plainly recognizable. It may be observed 

 further that the remaining chromosomes are quite different in 

 size, and it may be possible within reasonable limits of cer- 

 tainty to pick out one or more other chromosomes in each cell. 

 Unless this could be done for each element, however, it would 

 not definitely prove that all the chromosomes are distinct and 

 recognizable structures. The actual recognition of two ele- 

 ments in each cell of the same generation and its ancestors or 

 descendants in other generations goes far, however, to render 

 probable the individuality of each chromosome. 



Beyond this point studies upon the Orthopteran cells will not 

 permit me to go ; but Montgomer}' - has been fortunate enough 

 to find in Peripatvs an object in which he considers it possible 

 to demonstrate the continuity of the chromosomes from one 

 generation to another, and their fusion by pairs in the early his- 

 tory of the spermatocyte to bring about the reduced number. 

 This is, in the main, a logical conclusion to my own work, and 

 I am therefore bound to regard his results as probably correct. 

 While doing this, however, I recognize that the absolute proof 

 he brings forward in support of his hypothesis is very slight. 

 [ consider any deductions based upon observations of linin 

 structures as very insecure, and it is upon these that Mont- 

 gomery principally relies to demonstrate his theory. Further 



