SOMATIC CHROMOSOMES IN VICIA SlÇ 



The points in which the présent work stands in harmony with that 

 of other writers hâve appeared in the course of the description. It now 

 remains to consider certain points of disagreement. 



The chief différence arises through the absence of the important 

 prophase stages from previous accounts of Vicia. According to Lunde- 

 GÂRDH (09, 10, 12 1?, c) and Fraser and Snell (ii) the threads appear from 

 the resting net ah'eady double and remain so until metaphase, in contrast 

 to the opinion of Bonnevie (08, 11) who in other material sees them at 

 first single and later becoming double. In rVc/cz the writer has occasionally 

 seen images giving rise to an idea of duplicity in the very early prophases 

 but they are far from being the rule. In Laindegârdh's figures many 

 strands are single and in others the double nature is none too évident. In 

 fact it is not without difficulty that any definite conception is formed from 

 thèse figures of the very early prophases {12b, plate 18). But it is suflicient 

 to say that the descriptions and figures of both Lundegàrdh and Fraser 

 and Snell are incomplète, in that they omit the critical stages. The same 

 statement applies to the works of Farmer and Digby (10), Dehorne (u), 

 and Granier and Boule (11). 



On the other hand, \ve hâve seen in Vicia images such as must hâve 

 been the basis of Bonnevie's figures. A comparison of our fig. 5 with 

 those of Bonnevie makes this évident. The similarity is even more striking 

 in the case of Alliiim (Grégoire, o5). The thin threads, often actually 

 spiral but more often only apparently so, hâve been recognized by Bonnevie 

 but hâve been so schematized that their true meaning is almost whoUy 

 obscured. 



The prophase figures 7, 8 and 9 from which Mûller (12) argues for 

 a - direct condensation - of the reticulate bands into chromosomes repre- 

 sent aspects paralleled in Vicia only in cells not properly fixed to render 

 clear the détails, as described at page 314. 



The results of Béer (12), Frisendahl (12), and Gates (12) on small 

 chromosomes hâve been mentioned in the description. 



In the telophase the figures of Lundegàrdh [12b, c) are again in- 

 complète, since the détails of alveolization, which constitute évidence of 

 the highest value for the solution of the question in hand, are largely 

 lacking. Cases of vacuolization almost wholly along the central région seem 

 to hâve formed the basis of illustration. Such cases we hâve indeed obser- 

 ved, but certain of the figures could hâve been produced from our prepara- 



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