ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 831 



Algae. 



New Genera of Seaweeds.* — Herr H. F. G. Stromfelt describes 

 several new species of seaweed from Iceland, and the following new 

 genera: — 



Hsematostagon. Thallus crustam maculae similem formans 

 duobus stratis contextam : 1) basali, simplici, membranaceo, matrici 

 arete adha^rente: 2) superiore, parenchymatico, cellulis in seriebus 

 verticalibus admodum regularibus dispositis. Fructus ignotus. 

 Belongs to Squamariaceae. 



Coilodesme. Thallus callo radicali affixus, inferne stipitiformis 

 solidus, superne cavus, duobus stratis constructus, quorum interius o 

 cellulis longitudinalibus membranis crassioribus, exterius e filis 

 transversalibus subdichotomis cellularum parietibus lateralibus 

 gelatinosis pseudoparenchymatice coalitis formatum ; cellular filorum 

 terminalcs endochromate largiore praiditas, in membranam epider- 

 maticam arete conjuncta3. Sporangia inter extrema filorum segmenta 

 sessilia. Among Chordariacese. 



Stragularia. Thallus crustam formans matrici arete adhrerentem 

 strato basali simplici membranaceo fila verticalia emittento con- 

 structam, quorum o cellulis apicalibus demum paraphysao et 

 sporangia sorum indefinitum formantia exeunt. Among Lithoder- 

 mateaa. 



Zoospores of Chlamydomonas.f — M. Breal has observed that 

 the zoospores of Chlamydomonas pulvisculus are remarkably attracted 

 by light, and that, with regard to the influence of rays of different 

 colours, blue, green, and red exercise this attractive power, but not 

 the yellow rays. The zoospores of Chlamydomonas remain for a long 

 time in a dormant condition after becoming fixed and invested with 

 cellulose before they germinate. 



Cooke's British Desmids.J — Dr. M. C. Cooke has issued four- 

 parts of his work on British clesmids, with coloured plates and letter- 

 press descriptions, uniform with his ' British Fresh-water Alga?.' It 

 is hoped that the work will be completed in about ten monthly parts. 

 Kalfs's ' British Desruidiere ' was published in 1848, and has long 

 been out of print, so that it cannot now be obtained, except at a price 

 beyond the reach of the ordinary microscopist, and even when 

 obtained, would necessarily be deficient in all the species which have 

 been found and identified during the past forty years. The book is 

 one that has long been felt to be needed by pond-hunters. It may 

 be expected to include about one-third more species than were figured 

 in its predecessor. The current parts contain figures of Gonato- 

 zygon, Sphserozosma, Onychonema, Hyaloiheca, Bambusina, Desmidinm, 

 Docidium, Closterium, Penium, &c. Measurements are given in milli- 



* Naturvet. Students'allsk. Upsala, March 16, 1886. See Bot. Oentralbl., 

 xxvi. (1880) p. 172. 



f Bull. Soc. Bot. France, xxxii. (1886) pp. 23S-9. 



% Cooke, M. C, ' British Desmids. A Supplement to British Fresh-water 

 Alga3,' with coloured plates. Parts I., II., III. and IV. 8vo, London, 1SS6, 

 61 pp. and 32 pis. 



