526 Theophilüs s. Paintek, 



in the first division, the second spermatocyte cells are of two kinds 

 and this is clearly shown in the spindles of these dividing cells. 

 In the cell shown in Fig. 41, the accessory chromosome is present 

 and has divided. In Fig. 43, the accessory body is lacking. This 

 difference is further shown in equatorial view (Figs. 42 and 44). 



I have not been able to follow the course of the ctetosomes 

 through the second division, but in equatorial view we may sometimes 

 find them , as shown by Fig. 42 C. Judging from other forms 

 studied, however, it seems quite probable that the ctetosomes divide 

 at this time. 



After the telophase the autosomes of the spermatids lose their 

 affinity for the stain and form a very diffuse reticulum (Figs. 45—48). 

 The hétérochromosome elements retain their dense form and appear 

 as distinct nucleoli. Figs. 47 and 48 are of especial interest, since 

 they show the presence of a very small densely staining body, in 

 addition to the accessory chromosome. This small body marked '-C" 

 represents, we believe, the ctetosomes which we have followed through 

 the maturation period. 



No attempt has been made to follow the transformations going 

 on in the spermatids. This has been done by Wallace, for Agalena 

 naevia, and by Bösenbeeg for a number of other forms. 



Numberofchromosomes. 



The diploid chromosome constitution of Maevia vittata is as 

 follows : 



Autosomes 26 



Accessory chromosomes 2 



Ctetosomes 2 



Total HO 



As pointed out, it has not been possible to make accui-ate counts 

 of the number of chromosomes present in the spermatogonial cells. 

 In Fig. 3, is shown a cell, in which twenty-eight chromosomes could 

 be counted. In Figs. 36 and 37, we have fiat equatorial plates 

 shown. Here there is little over-lapping and one may count thirteen 

 autosomes, which, of course, is the haploid number. A number of 

 other equatorial plates of the first maturation division have been 

 studied, only those which were fiat being counted, and the result 

 has been the same in every case. In Figs. 42 and 44, are shown 



