120 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
method of distribution in the maturation divisions, may always move 
the same way, 7. e., all the chromosomes brought into the egg may 
pass into the female-producing sperm. It is extremely doubtful if 
the last suggestion will prove applicable as a general rule, but the 
conditions in Gryllotalpa are interesting exceptions to what has been 
found in the Acrididae and Tettigidae.! 
Hartmann (’13) describes small chromosomes as dividing unequally 
in some male germ-cells of Schistocerca. In one first-spermatocyte 
cell he found two such chromosomes (tetrads) dividing unequally, 
and he found some cases of unequal division in the secondary sperma- 
tocytes. These observations, if correct, would lead one to suspect 
that he might have been dealing with a condition similar to that in 
Phrynotettix, except that in the first division, either both the small 
chromosomes divided sometimes reductionally and sometimes equa- 
tionally, or, while one of them followed this method, the other always 
divided reductionally. 
Bringing together the results of Baumgartner and Payne for Gryllo- 
talpa, those of Carothers for Acrididae, Robertson for Tettigidae, and 
my own for Phrynotettix, we may arrange a graded series of condi- 
tions beginning with (1) tetrad B, in Phrynotettix, which is unequal, 
but divides equationally in the first division; passing (2) to Ci, which 
divides with equal frequency either reductionally or equationally in 
the first division, and when dividing reductionally shows chance 
distribution with reference to the accessory; thence (8) to the unequal 
types found by Carothers and Robertson, which always divide re- 
ductionally in the first division but show chance distribution, and 
finally (4) to Gryllotalpa, where division is always unequal in the first 
spermatocytes, but the larger dyad always accompanies the accessory. 
Whether this series offers any possible explanation as to the origin of 
these unequal elements, and their different kinds of behavior, is prob- 
lematical. 
Robertson’s work deserves further consideration, because he has 
found two of the three possible combinations which would be expected 
out of a random recombination of two unequal elements which con- 
jugate. In the case of Tettigidea, he found the unequal tetrad in 
1 Postscript.— Unfortunately I had overlooked the results reported for Gryllotalpa vul- 
garis by Voinoy (’14), who found in the first spermatocyte metaphase an unequal pair of dyads, 
which separate so that sometimes the larger dyad and sometimes the smaller one goes to the 
same pole as the accessory chromosome. These results are in accord with those mentioned 
above for the Acrididae and the Tettigidae and it may be surmised that similar conditions 
perhaps obtain for Gryllotalpa borealis but have so far been overlooked. 
