Morphologie, Teratologie, Befruchtung, C5'tologie. 341 



Synapsis is a real contraction of the nuclear net and not a 

 growing away of the nuclear membrane from the nuclear network 

 as claimed by Lawson. 



The spirem is a direct transformation from the nuclear net. 



The hoUow spirem is a thick chromatin cord in which a longi- 

 tudinal split is only occasionally seen and only in parts of the 

 same. This split whenever present always closes up completely be- 

 fore the cross segmentation. 



The rearrangement of the spirem takes place which is referable 

 to the second contraction described for the lilies and other plants. 

 This results in an entanglement of loops and parallel parts of the 

 spirem which twist upon each other. Diiring this rearrangement 

 the transverse segmentation of the spirem occurs. 



Each bivalent chromosome is formed b}'' an approximation, 

 usually side by side, of different lengths of the spirem, which may 

 have appeared as loops or otherwise. Each bivalent is, therefore, 

 to be regarded as two somatic chromosomes that were previously 

 arranged end to end in the spirem. The approximation of two 

 somatic chromosomes, side by side, or otherwise, or their adherence 

 end to end to form bivalents, is not known as synapsis in botanical 

 literature, nor is it properly called a conjugation. 



The prevalent form of bivalents upon the mature spindle is the 

 large ring, although other forms exist. 



The daughter segments split longiludinally during metaphase. 

 This fission may be looked upon as a preparation for the second, 

 or homot3'pic, mitosis. 



In the construction of the daughter nuclei , the chromatin does 

 not pass into a finely divided State. The chromatin segments elon- 

 gate greatly, becoming wavy or zigzag, and form an interrupted 

 spirem by the union of a number of the free ends. This spirem is 

 disposed in the form of a wreath or crown open at both the polar 

 and antipolar sides. The ends of the chromatin segments do not 

 fuse into "Chromatinknoten" in the daughter nucleus. 



Jongmans. 



Orman, E., Recherches sur les dif fe ren ciation s cyto- 

 plasmiques (Ergastoplasme et Chondriosomes) dans 

 les vegetaux. I. Le Sac embryonaire des Liliacees. (La 

 Cellule. XXVIII. p. 365—443. PI. 1-4. 1913.) 



Le memoire consiste de deux parties La premiere contient un 

 aperQU historique sur les travaux anterieurs qui se rapportent aux 

 differenciations cytoplasmiques. Cet apergu permet ä l'auteur de 

 definir avec precision les questions qui se posent au sujet des for- 

 mations cjj-toplasmiques. Ensuite il decrit ses objets d'etude [Lilium 

 crocetcm et martaa:on, Fritillaria ivnperialis et Tulipa gesneriana) et 

 ses methodes de hxation. 



La seconde partie comprend les recherches personnelles, une 

 discussion generale et les conclusions suivantes. 



1. Dans une etude des structures cytoplasmiques, il est de toute 

 necessite de recourir ä un examen comparatif des resultats obtenus 

 par diverses methodes de fixation et de tenir compte des circon- 

 stances variees dans lesquelles celles ci peuvent etre employ^es. 



2. Les methodes „mitochondriales" mettent en evidence, dans 

 le sac embryonnaire, ä tous les instants de son evolution, des cor- 

 puscules dont les caract^res morphologiques et les allures h l'egard 



