Addenda 453 



the Cyanophyceae, and probably justify its being placed in an entirely separate 

 group of that division.' Griffiths' conclusions give unqualified support to the 

 suggestion made by the present author in 1904 that the Myxophycese should 

 be divided into the Glaucocystideas and the ArchiplastidesG (consult p. 40). 

 ********** 



In the Protococcales quite a number of new genera have been recently 

 described. In the Volvocacere Isococcus Fritsch (in New PJnjtologist, xiii, 

 1914), Platymonas G. S. West (in Journ. Bot. liv, 1916) and Dysmorphococcus 

 Takeda (in Ami. Bot. xxx, 1916) have been discovered, Platymonas being 

 a marine genus and the other two freshwater genera. There is also an 

 interesting paper by Grove (in New Phytologist, xiv, 1915) on Pleodorina 

 illinoiensis, in which a number of new facts are recorded concerning the 

 morphology and reproduction of this coenobiate type. 



Dispora Printz (in Vidensk. Skrifter, Kristiania, 1913) is a genus closely 

 allied to Crucigenia. Several genera have been described from Victoria 

 Nyanza by Woloszynska (in Hedwigia, Iv, ] 914) : Schmidleia Wolosz., 

 Schrasderiella Wolosz., Victoriella Wolosz., and Peniococcus Wolosz. All 

 are to be referred to the Selenastrea? of this work, but Victoriella is identical 

 with Tetradesmus Smith (vide G. S. West in Journ. Bot. liii, 1915, p. 83) and 

 it is doubtful whether Peniococcus can rightly be separated from Desmatractum 

 W. & G. S. West. Peniococcus Nyanzte would be better placed as Desma- 

 tractum Nyanza. 



The genus Quadrigula has been founded by Printz (in KgL Norske 

 Vidensk. Selsk. Skrifter, Trondhjem, 1915) to include two Algas previously 

 placed in Ankistrodesmus. This genus is also one of the Selenastrese and 

 probably quite a valid one. 



Another genus of the Selenastrese has just been founded by Teiling (in 

 Svensk Botanisk Tidskrift, x, 1916) under the name of Tetrallantos. The 

 colony is very similar to that of Schmidleia, the differences being specific 

 rather than generic, and it would probably be more correct to place 

 Tetrallantos Lagerheimii as Schmidleia Lagerheimii. 



The most interesting of all these new genera of the Protococcales is 

 Pliytomorula Kofoid (in Univ. California Pull, vi, 1914), a member of 

 the Ccelastrese consisting of a small compressed coenobium of 16 cells. It 

 occurred in the plankton of a reservoir at Berkeley, California, and the 

 ccenobium is ' of exceptional regularity and remarkable resemblance to a 

 lenticular egg with equal cleavage, in a sixteen-cell stage.' 



Concerning the genus CentrosphsBra, an investigation has just been 

 completed in the botanical laboratory of Birmingham University by Miss 

 B. M. Bristol. The results confirm the view expressed by the present author 

 on p. 212 that EndospJiwra Klebs and Scotinosphf&ra Klebs cannot be 

 separated from Chlorochytrium Cohn ; but, in addition, there is clear evidence 



