302 .ions Mori pftcrsen 



Is iiKiinly a marine- and ftrackisli-wator lonii; hul it lias. Iiowevcr, 

 been loiind in pure Iresli waler al several piaces. The Icelandic sample 

 orif^inates undoubledly from the shore or adjacenl regions. 



IV. Cylindrospermum Kiilzing. 



Cylindrospermum muscicola Kutz. 



Bornel et Flahault, Revision IV j). 254. liabenhorst Alj^cn nr. 93. 



X. Icel. Hot stream in XamuskanV water alkaline, temp. 35 '^ ^^/7 

 1914. On the marj^in of an outlet temj). 54 ") from l'xahver ^^/t 1914. 

 S. Icel. Laugarnar at Heykjavik ^Stp.;! 



Area: Eur.. As., Afr., Am. 



The species of Cylindrospermum do not seem capable of thriving 

 in arctic and antarctic regions to any great extent. The s|)ecic's in (pie- 

 slion grows as a rule on earth, but has also been mct wilh in waler, 

 however, and even in brackish water (West 1909 I ]). 24 2 . That I have 

 found it in Iccland at and in hot s|)rings is undoubledly not due to ils 

 being a true thermal alga, but sim])ly due to the lad that it cannot 

 grow in the country except in piaces wherc the hot springs causc a 

 higher temperature all the year round. Tiiercforc it may prcsumahly 

 be included in that group of southern species which in Iceland are met 

 With but at Ihe hot springs (Ostenfeld 1899 p. 243). 



III. SCYTONEMATACEÆ. 



I. Scytonema Agardli. 



Seytonema varium Kiitz. 

 Bornel cl I'laiiauil, Hcvision III p. 97. 



S. chrijsochlorum Kutz. Species Algaruni |). ;{05: Tal). |)hyc. II, lab. 

 19. lig. II." 



S. Icel. Laugarvatn; outlet from hot spring ^'' s 1914. 

 Area: Eur., As., Am., Austr., Alaska. 



The outlet from the hot sjiring at Laugarvatn formed a kind of 

 delta before it flowed out in Ihc lakc of the same name. Hight in the 

 middle of this delta, half in waler and half out of il, the alga in (jue- 

 slion grew and formed cushions about 1 cm. thick and up lo 5 cm. in 

 diameier. The lem|)erature of the outlet was 72° C; but in the algal 

 cushions Ihe temp. was but about 21 ° C. Thcse cushions ])roved laler 

 to consisl of a Scijtoiicnjd wilh thin, colourless. somewhal gelatinous 

 sheaths thai. when dried, were not capable <if retaining the form of Ihe 

 threads, shrinking conscfjuently lo a great extent. Aller having been 

 soakcd out in lactic acid Ihcy resumcd Iheir original form, The bi-an- 

 ching was scanty; somelimcs [wd branches were seen issuing side by 

 side, at pthcr times a solitary branch appeared. '\hv threads were 

 9—11 /' in (liani.. the Irichomes (i.e — 8 // in (iianiclcr. The transverse 



