488 Wisco7isi7i Academy of Sciences^ Arts, and Letters. 



seems to have also been clearly established bv Fairchild's re- 

 searches. 



Klebahn's figures of Spliaeroploea show by the presence of 

 a well defined spindle and distinct chromosomes that in that 

 alga the nuclei divide by a typical mitotic process. 



Golenkin (10) has recently studied the nuclei of various 

 green algae and has attempted to show that the nuclei in such 

 forms as Tlydrodiciyoii and Spliaeroploea correspond in struc- 

 ture to those in Spirogyra in that in the resting stage the choma- 

 tin material is collected in the middle of the nucleus in the form 

 of a larfre nucleole. Between this body and the nuclear mem- 

 brane the space is filled vdth a formless hyaline substance. 

 During the division stages the bodies corresponding to the chro- 

 mosomes of hiirher T)lants are diffei^entiated out of the central 

 nucleole-like mass. Golenkin thinks that this type of nucleus 

 is of a primitive character as indicated by its occurrence in 

 these lower forms, but it is quite probable that Golenkin worked 

 with poorly prepared material in which the nuclei were dis- 

 torted. Such a result can easily happen in connection with 

 forms whose nuclei are so small as those of Hydrodictyon. 

 But my figures show that the nucleole in this plant is the same 

 organ in structure and occurrence as it is in the nuclei of the 

 higher organisms. 



The discovery of special cilia forming organs in the anthero- 

 zoids of various Gymnosperms and Pteridophytes, by Webber 

 (33), Ikeno (14), Ilirase (13), Belajeff (3), and Shaw (22) 

 and the attendant discussion as to their homology has brought 

 into prominence the question as to the homologies of cilia bear- 

 ing organs in swann spores and other ciliated cells. 



In a paper on the Clilamydomodineae, Dangeard (G) discusses 

 at some length the question of the structure of the cilia bearing 

 organ in the swarm spores of those plants. lie thinks that the 

 cilia are attached to a small basal nodule just within the 

 plasma membrane. There extends from this nodule toward the 

 nucleus, according to Dangeard, a fine protoplasmic fibre, that 

 may or may not reach the nuclear membrane. The basal 

 nodule is thou2:ht by Dangeard to be equivalent to the blepharo- 

 plast of the antlierozoids of the Gymnosperms and ferns. 



