V CHROMOSOME IN MAN. 2U 



; v The t\\o a< -t-sory chromosomes pass undivided to one 

 t" the -pindle considerably in advance of the other chro- 

 \vith tin- re-ult that half of the daughter cells in thi> 

 division re< -i\e twelve, and half, only ten univalent chronic-. >im- 

 '1 hi- i- evidently the reduction division. 



4. The ten univalent chromosomes \vhich passed t<> the one 



ndary -perm e unite again in pairs, at least in the ina- 



j>ri form five bivalent chromosomes which appear 



at the e(|u.it'r of the spindle when the cell is ready for di\ i-ion. 



Tin di\i-ion lii-re is presumably an equation and not a >ecnd 



reduction di\i-i"M. judging from the size, shape and general 



a|i|K -aram , the resulting daughter chromosom Thus 



while . the- s|XTin.uiiU formed as a result of this division 



live chonv -.the latter are bivalent and equiv- 



.il< lit to ten of the somatic or spermatogonial chromo-'-nu ~. 



'Ih, -me -li^ln i that the secondary sjxTnuito, 



in.r. ion.ilK di\ile \\ith these chromosomes in their origin. il 



:diiion ol uni\.ilei 



5. ! 11 oi' tin- (\\il\.- i hronioMnnes which passed to the othrr 

 pol.- of tin- spindle in the primary s|xrmatocyte behave in 

 i iselj the s.uue way as descril)ed in the last paragraph. The 

 t\\, ies come to the equator of the spindle 



in i h d.irv s|H-rin.itoc\ te with the five bivalents thus 



making in .ill seven, l.uh accessory now divides so that the 



h receive seven chromosomes; that 



i-, ii\i liixalent |ihis t\\o accessory, or the equivalent of twel\e 

 uni\ alent i hroni"-' -ines. 



o. In reality, then, ol' the total number of spermatids, lull 

 h.i\e in .ill |noli.il.ilit\ recei\-ed ten. and half, twelve do plus 2} 

 uni\ alent chronio-omes. Inasmuch as the spermatids transform 

 direct l\ into s^-nnato/oa, there must lx- two classes of the latter 

 difleriiu \\ith i. to whether they have or do not have the 



t\\. ; iromosonies. 



7. It is a si-niiiiant fact that approximately half tin resting 



s|HTinatid- \\lun >trongly decolorized after iron-haematoxylin 



staining. -ho\\ two chromatin nucleoli and halt do not. h 



nis probable that these nucleoli may corn-pond to the ac- 



son diromos, uncs and are to lx? identilied \\ith the two 



