No. I.] SPERMATOGENESIS OF BATRACHOSEPS. -^^ 



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thickening of the chromosomes at the place where they are 

 bent makes it probable that the chromoplast is situated at this 

 point (Figs. ii8, 119). In the mitosis of the spermatocyte 

 I have not been able to affirm with certainty the presence 

 of chromoplasts, except in the umbrella stage, where their 

 presence is indicated by endochromatic granules. Again, in 

 the resting stages of the spermatid the chromoplasts, generally 

 one or two, are plainly definable, especially by the means 

 of the congo-thionin-ruthenium red-staining method. In the 

 resting stages of the auxocytes, which are especially favorable 

 for study, a stream of chromoplasm is seen to project from the 

 chromoplast to each leader, and each leader is more densely 

 stained in the parts nearest the chromoplast. I do not, how- 

 ever, consider it with certainty established that a flow of chro- 

 moplasm actually takes place, as the phenomenon of deeper 

 staining can also be explained by a greater attraction of chro- 

 moplasm in proportion as the chromoplast is approached. If 

 this latter supposition is the true explanation, then we must 

 also look for the source of the supply of chromoplasm else- 

 where, possibly in the parachromatic granules. 



Be this as it may, the observed facts warrant us in con- 

 cluding that the chromoplast is of the utmost importance in 

 the formation of the chromosomes, and that its function seems 

 to be to attract the leaders, to segregate and define the chromo- 

 somes, and perhaps, in a general way, to supervise the formation 

 and evolution of the chromosomic constituents of the nucleus. 



Chromoplasts are probably present in all nuclei, and probably 

 also in all chromosomes. They have been frequently con- 

 founded with true nucleoli, but their distinct nature has also 

 been recognized by many investigators, and in all recent bio- 

 logical papers they are both described and figured as being of 

 different nature from that of the so-called true nucleoli. In 

 many instances, however, they have undoubtedly been over- 

 looked, especially in nuclei in the bouquet stage, where they 

 often are so small that they can only be distinguished through 

 their endochromatic granules, the presence of which always indi- 

 cates that the object in question is actually a chromoplast, and 

 not a true nucleolus or linoplast. 



