CHROMOSOMES OF HIPPOXOE AND MOIRA. 171 



one of which appears a- though it might coiisi-t of two or more 

 chromo-omes crowded together. I was not able as were both 

 Ileffner and Baltzer to identify with certainty the Y's or hook 

 in such views. As these observers have explained, tin- onlinarx 

 rod- -(.-en in polar views appear as -mall black dots. Two of tl 

 in contact arc to In- interpreted as the closely apprised arms of 

 tht- Y--haped chromosome. Mi-s Hetfner's figures of the polar 

 viVu- of daughter up'iips of Toxopneitstfs chn >mo-.< mie- an- ver) 

 r ami her interpretat i -n of them i- undoubtedly correct. 

 I', 'I/IT aUo linds tin- V's in jtolar \ie\\- appearing as \\\<> closely 

 MI dots. In pl.ii- views ol /fippniioi' I ha\e often oli-iT\e<| 

 \\hat I al lir-t -ii|ipo- t -.l nii-hi In- , ( \'. Hr-ide- tlu- >mall round 

 doi~ ?\pic,il of the rnd--h.ipi-il hroiiio-onu--. one tind- in e\ ery 

 plaie a number <! ellijit ie.il I >odi<-- ot twi ce the size ol the ordinary 



do: The-t- one naliiralK inter|)r i- as ilu- t\\o arm- of a V 



\\iih theii .-in surfaces il.nirned lo-rther. In some cases 



a MIX (\idnii roii-i rielion ci lincident with their narro\\r-.| 

 diameter makes -;: : i an in:' 'lion imp-iaii\e. Thi- con- 



st rit "tii m i- not however evident in the majoriix of cases and v< 



often nmre ! tin-- illiplic.il bodic- appear than are calli-d lor 



b\ 'lie mini! -nrd i-lelllelll- ill IHf)f)iUl,' I . I 



In .ill cases th( n the <|ii<--tion i- -till open a- to \\liether llir-c are 

 \ '.id'-haped indi\ idii.il- or even, as i- unite po ible, 



oiil\ one rod \ ii-u ed obliquely. The latter po^ibilit v in add it ion 

 i" the dillicnhv |ire-enti'i| by untranslatable amorphous ehn>- 

 matin Imdies in these d.u in.ikr- an .iccnr.ite count 



impo^-ibli fhe number counu-d mo-t treiinent 1\- \\a- thirt\- 

 t\\o but in no mid I I -i 1 -nn- that the number counted was 



con 



M 



Thi 'I Moirn i- much better -niled to detailed -tudy 



than the I-L;^ of ////'/ I'lu- tendeiicx of the chromosomes 



to ero\\d together i- not so pre\alent. .\lthoiii;h my mall-rial 

 \\a- \ er\ limited and contained comparative!) leu -pindli-s -.,nie 

 general facts W< In-red \\hich il ma\- be worth \\hile to 



rd. 



5 polar \ iew of the ei|iiatorial plate of the lir-t 



Mu-ntation nucleu-. A- alreadx- stated the chromosomes are 



