298 SUiMMAKY OF GUKRKNT KP:8EAKCHKS RELATING TO 



is that with three horns, a form which in the Kochel lake has only a 

 7 p.c. representation. On the whole, these forms from the "\Yigry lake 

 resemble those from the Alpine mid-European or Northern lakes ; 

 which refute.s the theory of local variations of the organism. Tem- 

 porary variations in the formation of horns in the Wigry lake is con- 

 sidered improbable by the author. Special attention is drawn to the 

 occurrence of five plankton epibionts, which are enumerated. 



E. S. G. 



Notes on the Systematics of Fresh-water Algae. — E. Xaumann 

 (Ark.f. Bot., 1921, 16, No. 2, 16 pp., 12 figs.). A series of five notes 

 on algge of systematic interest, which have attracted the author's atten- 

 tion during years of biological study of fresh-water algse. 



I. On SideroceUs, a nmv section of the genus ChloreJla {Beyer hicJc). — 

 This section is formed for the reception of a species which appeared in 

 a pond at Ugglehult in Smaland, Sweden, after befoulment with fish- 

 and flesh-meal. The cells, not exceeding 8 /x, are planktonic and round- 

 ish, having a green cup-shaped chromatophore, and are surrounded by 

 a brown warty membrane. Reproduction is by autospores. The warts 

 on the membrane consist almost entirely of iron oxide, and in considera- 

 tion of their chemical morphology they are placed in a special section 

 of Clilorella. Three species are described, two of which occurred in an 

 open-air basin in the Botanic Garden of Lund. 



II. On some new species of the Helophil nannoplanJcton. — Formal 

 diagnosis of five new species and varieties formally submitted to 

 Lemmermann for description in a proposed work on Swedish plankton. 

 They are already known as forming constituents of " water-bloom." 



III. Chrysococctis cordifonnis sp.n. — A description of an organism 

 occurring in the intestinal-contents of Entomostraceaj. Owing to a 

 failure to separate off living material by centrifugal action, the author 

 is unable to draw up a complete diagnosis, but he puts forward the 

 present account with a view to eliciting further information. 



IV. Brachionococcus, a neiv genus of Chlorophyceae. — K description 

 of an alga found some years ago in an investigtition of the influence of 

 certain refuse matters on the biology of fresh water. It is fairly round, 

 not exceeding 7 • 5 /x diam., has one parietal chromatophore, and con- 

 tains starch. Reproduction is by autospores in the manner typical of 

 Chlorella. Occasionally the daughter cells remain connected by delicate 

 strands to the old remains of the shell, forming a kind of transitory 

 colony. 



V. Nannochloris, a neiv genus of Chlorophycese. — The organisms in 

 question are very small, 2 ' 5 //.-3 • 5 fx. Each has one parietal chromato- 

 phore and an unsculptured, though in preserved material sharply 

 marked, membrane. Reproduction by simple division. No colonies. 

 Gelatine not present, or at the most in irregular scattered filaments. 

 Two species are described. The systematic position of Nannochloris is 

 probably near Nahnochloster Pascher. E. S. G. 



Notes on the Biology of Fresh-water Alg-ss. — E.Naumanx (Ark.f 

 Bot., li)21, 16, No. 1, 11 pp., 7 figs.). The first of a series of notes. It 

 is entitled, " On the Occurrence of Iron Oxide in a Species of the Genus 



