W. J. BAUMGARTXER. 



Very frequently it lies just outside the nucleus so that there 

 seems to be but one dividing membrane between the two 

 (Fig. 25). It may be entirely away from the nucleus show- 

 ing the two walls very distinctly (Fig. 26). In one case 



1 found the spindle between the accessory vesicle and the 

 nucleus (Fig. 24). In other cases the accessory lies entirely 

 in or partly in the other nucleus (Fig. 27); but in every case 

 it has its ozcu vesicular ivall around itself, and docs not form 

 part of the nucleus. Of course, the accessory is found in only 

 one half the cells. 



When the second spermatocyte spindle is formed the accessory 

 enters the equatorial plate and can not always be distinguished 

 because of the crowding of the chromosomes spoken of above 

 (Figs. 28 and 29). In a few cases I could distinguish the indi- 

 vidual ones and count them (Fig. 31). Here the accessory is 

 marked by its size and characteristic shape. But as soon as all 

 the chromosomes divide and move apart in anaphase, they can 

 be counted in almost every cell. The accessory again lags 

 behind but usually not so much as in the earlier stages. Figs. 

 32 and 33 give side views and Figs. 34 and 35 almost polar 

 views of the anaphase stage ; Figs. 32 and 34 show the accessory 

 and Figs. 33 and 35 lack it. Figs. 34 and 35 are very interesting 

 because they were found side by side in a cyst and indicate the 

 absence of the accessory in one half and its presence in the other 

 half of the cells. The accessory in the telophases and in the sper- 

 matids has been described in my former paper to which readers 

 are referred for its farther history. 



THE ORDINARY CHROMOSOMES.. 



While the above description of the accessory applies equally 

 well to either species of Gryllus, what follows applies only to G. 

 doinesticus. G. assiini/as shows some differences of size and 

 shape in the ordinary ! chromosomes, but it is not at all marked. 



1 At first I was inclined to adopt Montgomery's (26) terms homochromosome 

 and heterochromosome to distinguish between the ordinary chromosomes and the 

 accessory. But upon reflection it seemed to me it would lead to confusion with the 

 use of the words heterotypic and homotypic. If the terms were adopted then we 

 should have both homochromosomes and heterochromosomes in the homotypic divi- 

 sion as well as in the heterotypic. This mixing of terms seems undesirable. 



