418 SUMMARY or CURRENT RESEARCHES RELATING TO 



of formation of the antherozoids of Muscineae and of Vascular Cryptogams, 

 but differing from them in the absence of a vesicle formed from the 

 cytoplasm of the mother-cell. 



The details of the technique employed in this investigation are pro- 

 mised later. 



Algae. 



Effect of dilute Acids on Algae.* — Dr. W. Migula states that all 

 acids, and especially mineral acids, have a poisonous effect on Algfe ; 

 but some species are much more susceptible to their influence than 

 others. Thus Volvox globator is killed in a few hours by a • 002 per 

 cent, solution of phosphoric acid which Spirogyra orbicularis will with- 

 stand for many weeks. It is a remarkable fact that growth of the cell 

 will still continue after cell-division has been completely interrupted ; 

 but this continued growth takes place in length only, not in diameter, 

 and goes on until the cell has attained three to four times its normal 

 length. Assimilation is arrested by all acids, and the chlorophyll-bodies 

 are gradually bleached. 



Structure of the Frond of Champia parvula.| — Mr. R. P. Bigelow 

 publishes a further account of the structure of the frond of this sea-weed. 

 It is hollow and divided into chambers by nearly horizontal diaphragms, 

 and with filaments running longitudinally clcss to the inner wall and 

 passing through the diaphragms. All the filaments in each chamber 

 have projecting from their inner side one or two small globular or pear- 

 shaped "bulb-cells." The wall or cortex of the frond and the dia- 

 phragms are all composed of a single layer of nearly equal cells, and each 

 filament consists of a single row of long cylindrical cells. Mr. Bigelow 

 finds the apex of the frond to be occupied not by a single apical cell, 

 but by a cluster of nearly equal apical cells, each of which is the apex 

 of one of the longitudinal filaments. The diaphragms and the bulb-cells 

 are all formed by outgrowths from the filaments. 



The structure of the hollow-chambered frond of Lomentaria Bailey- 

 ana is somewhat similar. 



Askenasya polyniorpha.| — Herr M. Mobius corrects, in one respect, 

 his previous description of this new fresh-water Floridea. The cushions 

 found attached to the CTiantransia-like filaments he now believes to have 

 no connection with them, but to be colonies of an epiphytic Cyanophycea, 

 the rare Onocohyrsa rivularis. 



Colouring-matter of Bangia.§ — Herr F. Noll describes Bangia 

 fusco-purpurea of the Gulf of Naples as having the outer cell-layers of 

 its frond of a very gelatinous consistency, which serves as a protection 

 against the great extremes of drought and moisture to which it is 

 subjected. The different cells in the same frond, and even in the same 

 filament, vary greatly in colour between intense red-brown and blue- 

 green, the most common being a dirty brown-red ; but the colouring 

 matter resides in the chromatophores alone, the cell-sap being always 



* ' Ueb. d. Einfluss stark verdunnter Saurelosungen auf Algenzellen,' Breslau, 

 1888 (2 pis.). See Biol. Gentralbl., viii. (1889) p. 737. 



t Proc. Amer. Acad. Boston, xxiii. Part 1 (1888) pp. 111-21 (1 pi. and 1 fig.). 

 Cf. this Journal, 1888, p. 623. 



X Ber. Deutsch. Bot. Gesell., vi. (1888) pp. 358-60. Of. this Journal, 1888, 

 p. 93. V / i-i- 



§ Arbeit. Bot. Inst. Wiirzburg, iii. (1888) pp. 489-95 (1 fig.). 



