ZOOLOGY A^^) botany, microscopy, etc. 375 



Thallophyta. 

 Algae. 



Plankton-phase and Plankton-rate. — A. H. Church {Journ. of 

 Bot., 1919, 57, Suppl. iii., 8 pp.). An account of pelagic plankton, its 

 meaning and importance in relation to higher plant-life. Many higher 

 plants and animals "retain evidence of their plankton origin. By 

 " plankton-rate " is meant the amount of cytoplasm in millions of spores 

 or other organisms per litre of sea-water — a mere empirical means of 

 estimate, based on Lohmann's observations at Kiel ; and examples of 

 this are cited and compared with the spore-output of the male fern and 

 of Araucaria brasiliensis. The phytoplankton life is probably limited 

 by the available supplies of nitrogen and phosphorus in sea-water, while 

 animal plankton is limited by the oxygen supplies. A. G. 



Melosira RcBseana Rabenh., a Luminous Diatom. — B. Schroder 

 {Ber. Deutsch. Bot. GeseJL, 1916, 34, 796-800 ; see also Bot. Gen- 

 tralbl., 1918, 137, 2?>). Record of 31. Roeseana, found by the author in 

 a grotto on the eastern side of Zobtenberg, in Silesia, where it formed a 

 dark chocolate-brown, soft covering, 1-3 mm. thick, on the inner, dimly 

 lighted, be-trickled wall. Although the sun was on the other side of 

 the mountain, there could be seen, at one particular angle of vision, 

 brilliantly green luminous patches. The date was October 29, 1916. 

 The main constituent of the brown slime was 31. Rmseana, but Fragilaria 

 virescens Ralfs, Pinnularia borealis Ehrb., Hantzschia amphioxys Grun. 

 were present in small quantity, as well as single specimens of Synecho- 

 coccus aeruginosus Naeg., and two species of Cosmarium. The reflec- 

 tion of the green light is ascribed principally to 31. Roeseana, and is 

 probably caused by the same process as in Schistostega protonema. 

 Whether the globular auxospores only are luminous, or whether the 

 vegetative cells form a cylindrical mirror as well, is uncertain. Nowhere 

 is this luminosity of 31. Ro&seana mentioned in botanical literature, due 

 possibly to its having been overlooked. It may be also that it is only 

 luminous when it is present in great quantity, or, on the other hand, 

 when it has a rich growth of auxospores. E. S. G. 



Remarks on certain Adriatic Plankton Bacillariae. — B. Schussnig 

 {Sitzungsber. Ksl. Akad. Wiss. Wien, 124, Abt. 1, 1915, 377-406, 

 14 text-figs. ; see also Bot. Centralbl., 137, 6). A preliminary report on 

 the observations made during the cruise of the "Najade" in 1913. A 

 systematic enumeration of the Bacillarife is given, with remarks on the 

 distribution, morphology, and systematic position of each. Rhizosoletiia 

 calcar-avis Schtze. and R. alata Brightw. are very variable in form. 

 Chsetoceras Janischianum Castr. is an antarctic form and variable. 

 C. dichdeta is however distinct from it, and must not be referred to it. 

 New species and varieties are described. Many of the records are new 

 for the Adriatic, or have very rarely been found there. E. S. G. 



Remarks on the Bacillariaceae Flora of the Numburg Stream. — • 

 Quelle {31itt. Thiiring. bot. Ver. A^.F., 1916, 33, 68-9 ; see also 



