SEGREGATION OF HOMOLOGOUS CHROMOSOMES 479 



would seem to be about the same. Voinov recognizes this 

 difference, he says (p. 474) : 



II s'ensuit que le chromosome accessoire est distribue seul a un 

 pole et le bivalent entier avec lequel il etait associe va au pole oppose. 



Ce bivalent done, comme le chromosome accessoire, ne se divise 

 pas dans la premiere mitose de maturation. Cette maniere de se com- 

 porter constitue une difference avec les chromosomes multiples decrits 

 par Sinety et Clung. 



That is, while its structure is the same, its behavior is differ- 

 ent. It will be obvious to the reader that this chromosome 



i 



\n 



Text-fig. 3 1 'Chromosome en L,' de Sinety, plate III, figure 93. 



2 Hexad multiple, McClung, '05, p. 309, figure 3. 



3 'Chromosome -L,' Voinov, '14, p. 473, figure 8c. 



4 Late second spermatocyte metaphase of Tclement bivalent' Voinov, p. 

 488, figure 16c. 



5 'La grande tetrade,' Voinov, plate XXIV, figure 32L 



6 'L'idiochromosome, XY,' Voinov, Plate XXIV, figure 29. 



corresponds both in form and in behavior in the individual 

 with the J-shaped tetrads described in this paper. But, if it 

 does correspond, one would expect certain individuals to contain 

 in its place a rod-shaped tetrad and others a ring of the Steno- 

 bothrus type. That such a ring occurs in Vomov's material 

 may be seen in his figure S2t, plate 24, or my text figure 3, 5. 

 While he has material from fifty animals, it is impossible to 

 judge how thoroughly it has been studied from the standpoint 

 of the occurrence or non-occurrence of this 'hexad.' The only 

 direct statement is in regard to a count to show the distribution 

 of its parts in relation to those of an unequal pair. This 



