514 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
With regard to the systematic position of the Labyrinthulese, Zopf 
divides the highest order of the Mycetozoa, the SorophoresB, into two 
sub-orders, the Acrasiese and the LabyrinthuleaB. The former are 
characterized by having pseudoplasmodes, and by the sori being capitate, 
naked, and either stalked or sessile ; they live on dead parts of plants, 
dung, fungi, &c., and are divided into two families, the Guttulinese and the 
Dictyostelieae. The Labyrinthuleae have filiform plasmodes ; the sori are 
naked or imbedded in solid hyaloplasm, and sessile. They are partly 
saprophytic, inhabiting dung or salt or fresh water, partly parasitic, and 
comprise only the two genera Ldbyrintliula and Diplophrys. 
Protophyta. 
a. Schizophyceae. 
Lyngbyese.* — M. M. Gomont now gives a monograph of the second 
tribe of the Oscillatoriacese, the Lyngbyeae, distinguished by the sheath, 
when present, enclosing only a single trichome. They are divided into 
two sections, according as the trichome is septated or not. The first sec- 
tion is again divided into two sub-tribes, — Lyngbyoideas in which the 
filament is simple or pseudo-ramose, the sheath firm, sometimes dusky 
yellow, the trichome always straight at the apex [Plectonema 8 species, 
Symploca 11 species, and Lyngbya 21 species, including Leibleinia) ; 
and Oscillarioideae, in which the filament is simple, the sheath thin, 
always hyaline, mucous, more or less diffluent, apparently wanting in 
some species, the trichome often curved at the apex (Phormidium 29 
species, Trichodesmium 3 species, Borzia 1 species, Oscillatoria 38 species, 
and Arthrospira 3 species). The second section consists of the sub- 
tribe Spirulinoideae, characterized by the trichome being twisted into a 
regular spiral, and of the single genus Spirulina 9 species. The follow- 
ing new species are described : — Plectonema purpureum , Symploca 
atlantica , S. Isete-viridis , Lyngbya Bivulariarum , Phormidium Crouani , 
P. Setchellianum , Oscillatoria Aghardii i 0. simplicissima , 0. acuminata , 
0. numidica , Spirulina Nordstedtii. 
New Genera of Schizophycese.f — Among a number of Freshwater 
Algse obtained from Algeria, M. C. Sauvageau describes several new 
species, and the following new genera of Schizophyceae : — Synechocystis , 
nearly allied to Synechococcus , but with perfectly globular cells ; Tapi - 
nothrix, with the following diagnosis, — Filaments without heterocysts, 
very slender, simple, attenuated from a slightly thickened base, not pro- 
duced at the apex into an articulated hair ; sheath slender, very narrow, 
continuous, usually open above from the escape of hormogones; near 
Schizothrix and Amphithrix. 
Biology of Diatoms.f — Dr. P. Miquel discusses in detail the various 
modes in which diatoms multiply. The diminution in the size of 
diatoms is not in exact proportion to the number of bipartitions, which 
is retarded by the constant decrease in the thickness of the connectives. 
* Arm. Sci. Nat. (Bot.), xvi. (1892) pp. 91-256 (7 pis.). Cf. this Journal, 1892, 
p. 838. 
t Bull. Soc. Bot. France, xxxix. (1892) Sess. Extraord., pp. civ.-cxxviii. (1 pi.). 
t Ann. de Micrographie, iv. (1892) pp. 529-58 (9 figs.). Cf. this Journal, 1892, 
p. 655. 
