410 SUMMARY OF CURRENT RESEARCHES RELATING TO 



phyceBB (wherein the limitations of the latter are defined), Habitat, Cells, 

 Phycocyanin, Cellular Membrane, Teguments, Cellular Associations, 

 Cellular Scission, Growth and Ramification, Heterocysts, Propagation, 

 Fragmentation, Conidia, Planococci, Hormogonia, Hormocysts, Spores, 

 Polycysts. Then follows a systematic synopsis of the MyxophycejB, 

 drawn up with full recognition of the unstal)le value of genera and 

 species owing to their polymorphism under varying conditions. Diagnoses 

 are given of Orders, Sub-orders, Families, etc. 



Part II. is devoted to a detailed consideration of Stigonemacete, 

 the highest type of Myxophycea^. This family is divided into Stigo- 

 nemeas and Diplonemese, according to whether the filaments possess 

 trm or spurious ramification. A conspectus of genera gives diagnoses 

 of fourteen genera for the former and five for the latter, three being 

 new to science. The genera are then treated separately in considerable 

 morphological and structural detail, most attention being paid to those 

 genera which are usually regarded as possessing many species, such as 

 Stigonema, Hapalosiplion , etc. The extraordinary adaptability of species 

 of Myxophyceffi has formed a special study of the author, and is here 

 discussed. About 200 species of Scytonema have been described, of 

 which only seven or eight are valid ; 300 species of Oscillator ia are reduced 

 to about a dozen ; for Stigonema only five species are recognized out of 

 fifty. The author states his intention of discussing the remaining 

 families of Myxophycete in the same detail in a later publication. 



E. S. G. 



Chondriome of a Green Alga, Coccomyxa soloringe Chod. [a 

 Correction].— M. et Mdme. F. Moreau [Comptes Rendus Sor. Biol. 

 Paris, 1916, 79, 211-2; see also Bot. Centralbl., 1919, 140, 89). 

 In a previous publication the authors have described, in the cell of 

 Coccomyxa solorinse (a green alga with a special chloroplast), granulose 

 formations which they likened to mitochondria. This opinion was 

 founded on a large number of experiments. In particular, the authors 

 then rejected the hypothesis of metachromatic corpuscles, whose 

 existence they had not been able to reveal in the Coccomyxa cell outside 

 the chromatophore. These first researches on metachromatic corpuscles 

 of Coccomyxa were carried out on thalli in which most of the gonidia 

 show metachromatic corpuscles limited exclusively to the chromatophore. 

 Recent observations have demonstrated, however, the existence of these 

 same corpuscles distributed generally all through the algal cell, outside 

 the chromatophore. Consequently the authors feel they can no longer 

 affirm the existence of chondriosomes in the protoplasm of the cell of 

 C. solorinse outside tlie parietal chloroplast which it contains. The 

 granules previously described by the authors as mitochondria seem now 

 to be metachromatic corpuscles. Consequently, C. solorinse does not 

 constitute, as the authors had supposed, an exception to the rule 

 formulated by Guilliermond, according to which green algie having a 

 special chloroplast lack a chondriome of the usual character. E. S. G. 



Chondriomes in Chara. — A. J. Riker (Bull. Torrey Bot. Club, 

 1921, 48, 141-7, 1 pi). An investigation of the origin of the chon- 

 driomes or staining granules in the cells of Chara. The author states 



