Studies on Chromosomes 7 



mosomed a sa long worm-shaped body obviously without a mate, 

 (Fig. i, </-/). The remaining twelve chromosomes may be 

 grouped in symmetrical pairs (indicated by numbers in Fig. I, 



h 



// 







> 







A 



(' 



3 



* lX M 



** ! ^ a- *l / 



5 



3 4 



FIGURE i l 



Protenor belfragei. a, Anaphase of second spermatocyte-division; b, c, sister groups, from the 

 same spindle, polar view, second spermatocyte-division; d, e, /, spermatogonial groups; g, h, groups 

 from immature ovaries, probably oogonia; i, group from dividing follicle-cell. 



d, ^), though the members of each pair may occupy any relative 

 position. Of these six pairs, one (2, 2) is always much larger than 

 the others, its members being approximately half the size of the 



J A11 the figures are drawn to the same scale. In all, h denotes the heterotropic chromosome, ; the 

 idiochromosomes (large and small in some cases lettered I and i respectively), m the paired micro- 

 chromosomes, and i the smallest pair of ordinary chromosomes. 



