(). WiMJK i:j7 



A cyU)lo^ic«l iiivi'Mi-ijfiition, carried nut fsm-ntially with a \u\\ U) 

 aaccrtaining the chnmiosomc munlHT. j^avi* thr followiu^r rcMult. 



hifln/rus odttratuji L. 



The rhn»iiu»8«>inett art* largr aixi soim-whal. <'l<n>^Mt<'<l in lh»- hrtin*- 

 typic uietJiphiuH*. Thry '^re pifsviit. tn thr iiumlu'r nl' 7 (=./) (Figs. 1 

 ami 2). Thort' is no ditVrrcncT, <»n the whoir, in the si/c of thr dinVnnt 

 chn)nu»Si»nu»s. Splitting and transition to the ;m.i|)h}i.m' prorrcd fairly 

 regularly. Onv of the chromosome |>airs am, however, at limes l»e 

 sepanite<i slightly earlier than the remainder (Fig. .S). The heterotypic 

 tolophjise may often give an impression that the chromosome number 

 isgToati»r than seven, owing t<> the fact that the chromosomes at this stage 

 are bent to an angle, and also exhibit splitting in the plane through 

 which the subsequent homoeotypic division takes place. The chromo- 

 somes being bent to an angle (the angle pointing toward the pole of the 

 nuclear spindle) will in a certain position each appear {is two separate 

 chromosomes (schematically shown in Fig. 4) and as the chromosome is 

 further split in the plane of the angle, we find, extremely often, apjmrent 

 groups of four chromosomes, to the number of seven, i.e. 28 altogether 

 (Fig. 5). Fig. 6 shows the chromosomes in the metaphase of the homoeo- 

 typic division; here also we Ciin with great certainty count seven chromo- 

 somes in eiich of the two nuclear plates of the spore mother cell. In 

 the anaphase of the homoeotypic division also, we may find what would 

 seem like more than seven chromosomes, the chromosomes here being 

 likewise bent to an angle, though not split. 



An investigation of the chromosomes in somatic cells showed entire 

 agreement with the figure found in the haphjphase, i.e. 14 (Fig. 7). As 

 is usually the case, the chromosomes here were of slenderer form than 

 during reduction division. 



Lathyrus latifolius L. 



This j>erennial species appeared in every respect as L. odoratu.s, and 

 the cytological picture for the two species is so uniform that prepara- 

 tions of the one might be taken for those of the other. Not only is the 

 chr«»mosome number likewise seven, <us the heterotyi)ic metaphase in 

 Figs. 8-9 shows, but the chromosomes themselves are also entirely alike 

 in size and shape. Here, as in L. odoratua, twice the number could be 

 counted with pertect certjiinty in somatic cells (Fig. 10). 



These two species, then — the oidy species of Ldthijrns hitherto 

 investigated — present an instiince of the ordered icgularity with which 

 in larger or smaller systematic groups in the animal and veget<ible 



