ORTHOPTERAN SPERMATOGENESIS 687 



quently appear two spiremes which, by parasynapsis, become 

 a double one, and this then divides by transverse fission into the 

 reduced number of chromosomes, 17. These are of the sizes 

 found in the spermatogonium and represent them in the paired 

 condition. (2) The forms of chromosomes in the first sperma- 

 tocyte prophase are rings, figures of 8, etc., in which the open 

 space represents the plane of fusion between the spiremes— it is 

 interchromosomal. (3)' By concentration the metaphase chro- 

 mosomes are formed from those of the prophase. (4) Upon the 

 spindle the rings are so placed as to lie extended in its axis. Rods 

 also occur in the same position. (5) The rings break into half 

 rings or V's whose enclosed space is the interchromosomal cleft 

 between the spiremes. (6) There is no detailed consideration 

 of fiber attachment. (7) In the anaphase there appear double 

 V's whose separation is due to the longitudinal split of the chro- 

 mosomes. (8) Through the movements of the chromosomes in 

 the first spermatocyte mitosis a reduction division is accomplished. 

 The accessory chromosome does not divide at this time. (9) In 

 the second spermatocyte an equation division occurs. 



Granata ('10) has studied for the maturation phenomena of 

 the chromosomes the material employed by Giglio-Tos in his 

 investigations of mitochondria, which was derived from the 

 European genus Pamphagus. As has already been noted in 

 considering the sperm.atogonia, this form appears to show different 

 numerical conditions from most other Acrididae. The conclu- 

 sions of Granata are as follows : (1) The number of chromosomes 

 is constant and the members appear as paired elements of definite 

 sizes. An unpaired accessory chromosome is present. A spireme 

 is formed in which the spermatogonial chromosomes lose them- 

 selves. There is no persistent chromosome individuality since 

 these structures are but the expression of chemical activities. 

 (2) The typical first spermatocyte chromosome is the cross 

 formed from a rod which has been twice divided longitudinally 

 and has then opened out part way along one of these clefts and 

 later, from the opposite end of the rod, along the other. Rings 

 are similar structures which, instead of opening out completely 

 along the second longitudinal cleft, have remained united at the 



