380 JOHS. BOYE PETERSEN 



have luul il in a livin^ slalf. I loiind scvi-ial speciinens ol' il in tlic 



abovc-mcnlioncd localily, sonic of tlicni witli ccH conlents. Sonictinics il 



occurred in small groups ronsistin«^ of 3—1 iiulividuals. 



Tlic loc-ality was ratlicr pec-iiliar. Al a licif^hl of f) 10 ni 



on llic healli iH'lween Isafjord and l'latcvri. on llic stony 



Hat suiToundinrt thc bcacon at llie lii<^hesl poinl. wcre 



foiind lu fis of PrasioUt crispa willi othcr {^reen algæ and 



sonic Dialonis inkM'niixed. The place no doubt oflen 



4 , ''?;■'■ serves as a hallini'-placc for Iravellcrs on font or on 



Arnniinthcs ntiq- , 



nura Schum. Cl. horseback, and one can hardly help Ihinkinf^ thai such 



(X 12001 a tull of alj^;e may have been brouj^hl up Ihere acci- 



deulaily by peo|)le or horses, bul tiie algæ seenied to 

 be in a llourishinjf condilion. 



One spccinien nieasured in 1. ll,5/(. br. 6.J //. sir. 16. The same species 

 was found in a sample of soii from HJork taken in 1925 by Molholm- 

 Hansen. Here I observed thai Ihe apical area of the hypothcca was 

 now broad. now narrow. In Ihe specimens in this sami)le the slriæ 

 secmcd to be somewhat finer, viz. 18 in 10 /< in both valves. 



Achnanlhidimn Heib. 



Achnanthes coarctata Hréb.) Grun. Cleve Syn. II, p. 192, V. Heurck, 

 Syn. PI. 26, lig.s. 17. 18. 



E. Icel. L. 70 — N. Icel. 253 - S. Icel. 302 — Vestmannaeyjar L. 399, 

 L. 400. L. 101, L. 403. L. 408, 409. 



The species seems to be most widely distributed in the northern 

 hemisphere and especially in arctic regions. Pfitzer mentions it as far 

 back as 1882 p. 405j as a terrestrial species. In Denmark il fre(}uently 

 occurs as an aerial alga (Hoyc P. 1915, p. 293j. In Swilzerland Meister 

 considers it rare 1912, p. 99), while v. Schonfeldts statements from 

 Germany (Pascher, Susswasserflora, H. 10. p. 58) would seem to indi- 

 cate that il occurs especially in "formations passageres^ (sensu Coniere. 

 As regards the arctic countries Lagerstedt states (1873. p. 49) that it 

 is fairly common in Spilzbergen and Jan Mayen, and occurs »on the 

 ground and among mosses«. 



In Iceland Os trup found it in 39 samples, while I have it from 9. 

 It may then pcrhaps be warrantable to assumc that it thrives about 

 ecjually well in water and in certain aerial localilies, though in Den- 

 mark it seems to be predominantly a terrestrial species. On the rocks 

 of the Vestmannaeyjar it was a character species, occurring in nearly 

 all the samples collccted partly from caves in a rocky wall at an alti- 

 tude of about 20 m above sea level, partly on rocks below hird clilfs. 

 In Ihe caves in (|ueslion it was found inter alia togelher wilh several 

 brackish water species. 



Achnanthes lanceolata Jirt'b.j Crun. CI. Svn. II, p.l'Jl. \. Heurck 

 Syn. PI. 27, ligs. 8— 11. 



"o" 



E. Icel. 128 - N. Icel. 162, 179, L. 215, L. 217 - S. Icel. 364, 372, 

 395 — Veslmannaevjar L. 403, 408. 



