476 BOTANICAL GAZETTE [December 



laboratory, is furnished with a luxurious display of long beautiful 

 hairs on the margin of its funnel-shaped thai] us, while such a hairy 

 growth has not yet been seen in cultures. It must be admitted, 

 however, that there is a difference between conditions in nature 

 and in cultures which may account for the difference in this 

 character; the young plant of Cutleria is found on the rock at a 

 depth of 1-5 meters, while the culture was kept in a tank where 

 the water was never deeper than 6-8 inches. Intensity of light, 

 temperature of water, its pressure, its movement, and other factors 

 may be quite different, and yet in spite of such a difference of 

 external environment, the zoosporelings of Aglaozonia developed 

 into erect structures of funnel-shape as in the young Cutleria 

 plants, and fundamentally different from the flat creeping expan- 

 sion habit of both parent forms and of the plants resulting from 

 fertilized female gametes of Cutleria. 



The young plants of Cutleria and the product of the zoospore- 

 lings of Aglaozonia in culture show not only the common habit in 

 their development and similarity in their outer morphological 

 characters, but also a similar cell structure, similar nuclear condi- 

 tions, and the same number of chromosomes. 



Discussion of cytological phenomena 



UNI\ 



The chief constituents of the resting nucleus of Cutleria and 

 Aglaozonia are the network and nucleolus. The network is com- 

 posed of two parts, granules and irregular fibrils in varying pro- 

 portions. The granules are of different sizes and some of them are 

 connected by very slender, irregular fibrils, or lie isolated usually 

 near the nuclear membrane. The number of granules in the nucleus 



more 



chromosomes 



may 



but the preparations never fail to show their presence. Both 

 granules and fibrils consist of chromatin. 



As a rule, there is only one nucleolus, and it lies quite free from 

 the nuclear network, with which it shows no visible physical con- 

 nection. Concerning the morphological function of the nucleolus 

 in algae, Strasburger (55, 57) published the view that the sub- 



