1912] BARRETT— BLASTOCLADI A . 367 



k 



seen (fig. 47). The two parts then round up (figs. 45, 53), separate 

 (figs. 49, 51), and appear as two large nucleoli. A wall is finally- 

 laid down between the daughter chromatin masses, and the two 

 nuclei result (figs. 44, 55). Frequently nuclei may contain three of 

 these bodies (fig. 50). Evidently one of the two daughter masses 

 of the first division divided before any nuclear wall separated them. 



In dividing nuclei stained with iron-alum hematoxylin, there is 

 a faintly staining homogeneous substance connecting the separating 

 chromatin masses, which suggests some sort of a spindle. Two 

 explanations suggest themselves: (1) that we are dealing with 

 direct nuclear division and that the faintly staining substance is 

 the cytoplasm contracted about the dividing chromatin masses; 

 and (2) that division is indirect and that the large chromatin mass 

 represents a single chromosome. 



It seems unusual, if not improbable, that such a highly differ- 

 entiated plant in so many respects should possess only a direct 

 method of nuclear division. The fact, however, that no sexual 

 organs are known for any of the species of the genus may have some 

 bearing on the question. Humphrey (3) found a very similar 

 nuclear division to take place in the hyphae of Achlya apiculata. 

 From all observations yet made, I am inclined to hold to the view 

 that we are dealing with a peculiar type of mitotic division. Further 

 studies concerning the question are contemplated. 



Since the species appears to be a new one, I add here a descrip- 

 tion giving the more important characters as observed by the 



writer. 



Blastocladia strangulate, nov. sp — Main 

 ided at the base into a number of rhi; 



oidal divisions; above 

 giving rise to a one to several times dichotomously or umbellately 

 branched system whose ultimate branchlets produce terminally 

 or subterminally zoosporangia and resting sporangia; definite 

 constrictions and perforated pseudo-septa at the points of branch- 

 ing. Zoosporangia, oval to nearly spherical (50-63 X 40-5 2 /*)> 

 possess several papillae of dehiscence, and produce a compara- 

 tively small number of rather large zoospores. Zoospores 12X8 ^, 

 with one to three cilia, usually one. Resting sporangia ovate to 

 nearly oval, with a truncate base, 45X35 PJ the wall consists of 



