286 NATHAN FASTEN. 



are seen arranging themselves. Here the chromatoid bodies can 

 also be clearly discerned at opposite poles. Each of these bodies 

 is surrounded by its characteristic clear space and may be easily 

 recognized from the ordinary chromosomes. 



In the metaphase period (Fig. 26), all of the chromosomes are 

 grouped in the equatorial plane and appear as large dumb-bells. 

 When the component bivalents of each dumb-bell are examined, 

 they are found to be large spherical bodies, about twice the size 

 of the spermatogonial chromosomes. Furthermore, these biva- 

 lents do not show the equational furrows where the equational 

 division of the second spermatocyte will take place. Binford 

 ('13), in describing this stage in Menippe mercenaria claims that 

 the chromosomes in the equatorial plate of one of his prepara- 

 tions were found to be ring-like in appearance. In other prepara- 

 tions which were destained to the degree of removing all the stain 

 from the cytoplasm and the achromatic figure of the metaphase, 

 this same investigator asserts that he could distinguish the indi- 

 vidual four chromosomes of each tetrad. In Cancer magister 

 no such results were obtained in spite of the fact that a great 

 many smears and sections were carefully examined. 



In polar views of the metaphase stage sixty chromosomes have 

 been distinguished (Figs. 27 and 28). These are generally oval 

 in shape; some of them being larger than others and they are 

 distributed throughout the equatorial plane. Figures 27 and 28 

 are drawings of polar views as seen in smear preparations. 

 Similar counts of polar views in sectioned material have corro- 

 borated this number for the reduction division. 



The chromatoid bodies always migrate undivided to opposite 

 poles of the cell. In many cases they occupy positions along 

 the spindle fibers (Figs. 26, 29 and 30), while in other cases they 

 may be seen in the cytoplasm (Figs. 31 and 32). When they 

 occupy positions along the spindle fibers, one would be easily 

 misled into regarding them as accessory chromosomes, especially 

 so if no attention were paid to the various stages of the growth 

 period. Wilson ('13) has cited numerous cases in which in- 

 vestigators have undoubtedly confused chromatoid-like bodies 

 with accessory chromosomes. After citing these instances, 

 Wilson, on p. 403, then makes the following significant remarks: 



