156 M. W. BLACKMAN. 



metaphase it is connected by mantle fibers to only one pole of the 

 spindle. 



As a result of the first spermatocyte mitosis fifteen of the 

 tetrads are divided longitudinally (equationally), while the one 

 remaining tetrad divides transversely (reductionally). The fail- 

 ure of the accessory chromosome to divide is, also, in effect a 

 reductional division. 



During the later stages of the first maturation division and 

 during the metaphase of the second spermatocyte, it is possible to 

 distinguish the daughter chromosomes derived from the several 

 types of tetrads, by their shape and their relations to the mantle 

 fibers. The individuals of the various types show the same size 

 ratio as exists between the chromosomes of the first spermatocyte, 

 although, of course, the actual difference in bulk is but half as 

 great. 



The above results seem to establish as a fact, or at least as a 

 very strong probability, that the chromosomes of Scolopendra 

 heros are distinct and definite individuals, which, under similar 

 circumstances, i. e., in the same cell generation, show a remark- 

 able constancy in form, relative size, and in their attachment to 

 the mantle fibers. This constancy of form, size and behavior, 

 affords a strong argument in favor of the theory of the individu- 

 ality of the chromosomes in this species in particular and adds 

 support to the evidence derived from the study of other forms, 

 to the general application of the theory. 



LABORATORY OF ZOOLOGY, ' 



SYRACUSE UNIVERSITY, 

 April ii, 1910. 



