DAVIS: SPERMATOGENESIS. 61 
the “accessory chromosome.” In a later paper McClung (:00) gave 
a detailed account of the spermatocytes and the maturation divisions 
in Hippiscus (one of the Acrididae). He concluded that the first 
maturation division is longitudinal, while the second is transverse, and 
that the accessory chromosome, like the other chromosomes, divides at 
both divisions. In the same vear Sutton (:00) found that in the sper- 
matogonia of Brachystola (one of the Acrididae) the chromusomes ex- 
hibit a remarkable degree of separation, for during the telophase of 
the secondary spermatogonial divisions each chromosome becomes en- 
closed in a distinct vesicle. Later these vesicles fuse at their polar 
extremities, with the exception of the one containing the accessory 
chromosome, which remains distinct throughout the resting stage. 
In 1901 de Sinéty, in an extended paper on the anatomy and physi- 
ology of the Phasmidae, published an account of the spermatogenesis 
of a number of Orthoptera belonging to several families. He con- 
cluded that both maturation divisions are longitudinal or equational, 
but that the accessory chromosome does not divide in the first divi- 
sion. ‘Thus only one half of the spermatids contain this chromosome. 
A little later McClung (:02*), in an account of the spermatocyte divisions 
of the Locustidae, confirmed de Sinéty’s account of the behavior of 
the accessory chromosome during these divisions. McClung also 
showed that during the spireme stage of the spermatocytes the acces- 
sory chromosome becomes converted into a long coiled thread. His 
account of the maturation divisions agrees with that previously given 
by him for the Acrididae. Sutton (:02) in an interesting paper showed 
that in the spermatogonia of Brachystola the chromosomes vary 
greatly in size, but that with one exception, the accessory, there are 
always two of each size, and that in the spermatocytes the bivalent 
chromosomes have the same size relations. He believed that the 
bivalent chromosomes were formed by the conjugation end to end of 
the individuals of each pair of the spermatogonia. Sutton agreed 
with McClung, that the second maturation division is the reducing 
division. 
In 1902 Baumgartner published an account of the metamorphosis 
of the spermatid in Gryllus, and later (:04) showed that in the sperma- 
togonia the accessory chromosome forms a large V-shaped structure, 
very different from the ordinary rod-shaped chromosomes. In the 
growth stages of the spermatocytes the accessory chromosome forms, 
as in the other Orthoptera, a deeply staining mass applied to the 
nuclear membrane, and divides only during the second maturation 
division. Baumgartner also believed that in the spermatocytes there 
