l66 CARRIE I. WOOLSEY. 



No. 416 broke up- badly so that it was difficult to find a perfect 

 division figure. However, a sufficient number were found to 

 determine the number and character of the chromosomes (Figs. 



13-14)- 



I found no distinctive feature in the number, arrangement, 

 or behavior of the chromosomes in the first five individuals of 

 this species (Figs. 13 to 29). There are thirty-five chromosomes 

 in each and their appearance is very similar to that noted in 

 individuals. No. 588 and 589. The accessory chromosome is 

 very prominent and in the majority of spermatogonial metaphase 

 figures it is found with seventeen of the largest autosomes on 

 the periphery, the remaining seventeen small ones being in the 

 center of the figure (Figs. 13, 15, 25-29). 



A most interesting feature was found however in the individual 

 No. 503. Instead of the thirty-five autosomes of the simple rod 

 type that were common to the other members of the genus as 

 well as species, I found here thirty-three rods and a large V- 

 multiple whose arms are of unequal length. When I attempted 

 to arrange the autosomes in pairs, I found two of the large ones, 

 numbers 16 and 14, without mates among the rod type but 

 corresponding in size to the arms of the V (Figs. 30 to 33). In 

 one cyst I found several perfect cells in spermatogonial metaphase 

 showing this size relation between the rods and the arms of the 



V (Figs. 30-31-33)- 



After satisfying myself that this multiple chromosome appears 

 in all spermatogonial metaphase figures, I examined cells in other 

 stages of growth. In the various phases of the first and second 

 spermatocyte cells I found the V still present. In the first 

 spermatocyte figures the rod mates were often still attached to 

 the arms of the V but the break could always be distinguished 

 more or less distinctly (Figs. 37 through 50). In first spermato- 

 cyte metaphase (Fig. 42), I found the V still attached to or 

 united with its -mates as were several of the rod chromosomes 

 also. In this stage I found fifteen rods without the two in the 



V and the accessory, making in all eighteen chromosomes in the 

 first spermatocyte. 



In the second spermatocyte division the accessory chromosome 

 divides longitudinally so that each daughter cell receives half. 



