

I 



t 



1907] CURRENT LITERATURE 



391 



frond of the fern, and the leafy axis of the club moss." When revolutionary ideas 

 are combined with evident lack of familiarity with the structures under discussion, 

 it is no wonder that confusion is the result.— J. M. C. 



Development of heterotypic chromosomes, — Two years ago Mother pub- 



mi mary 



pollen mother cells, and 



appeared/^ His paper consists of two parts: first, a statement of the results 

 of his studies of five angiosperms {Podophyllum peUahim, Lilium Martagon^ L. 

 candidum, Tradescantia vtrginica, and Galtonia candicans); and secondj a dis- 

 cussion of several cytological phenomena, reviewing the work of previous investi- 



chromosomes to hereditary characters. 



account of the possible 



The few points which he has specially emphasized in his own studies on 



these five forms are as follows: 



poll 



consists of a linin net, the ground matrix in which the chromatin is held. The 

 chromatin is in the form of very fine granules of uniform size or In larger aggre- 

 gations or clumps which are composed of smaller granules. (2) In s}Tiapsis he 

 has not found a union of two spirems. (3) The loose or hollow spirem which 

 has emerged from synapsis is of the double nature, which he believes to be due 

 to a new longitudinal spHtting that provides for the second division. (4) Seg- 

 mentation of this loose or hollow spirem into chromosomes takes place during 

 or following the second contraction stage. The second contraction consists in" 

 the arrangement of a large part of the spirem into loops that tend to radiate 



mass 



formed 



portions 



Each 



loop represents a bivalent chromosome, each parallel part being a single chromo- 

 some. The two parallel parts or chromosomes are arranged tandem, or end to 

 end in the spirem, (5) He seems to emphasize the 



point 



spirem into chromosomes. 



segmentation 



confirm 



Farmer and Moore, Schaefner, and Strasburger. His theo- 



point 



be 



all identity 



of such bodies is lost. He thinks granules in tlie resting nucleus should be con- 

 nected with smaller units, the pangens (following the terminology of DeVries); 

 and with a purely theoretical consideration of the pangens and their relation to 

 chromosomes and to heredity, the paper closes. — S. Yamaxouchi. 



XI 



MOTTIER, D. M., The development of the heterotypic chromosomes in pollen 



mother cells. Box. Gazette 40:171-177. 1905 



12 



heterotyp 



mother cells. Annals of Botany 21:309-347. pis. 27, 28. 1907 



