244 



Lyngbye has labelled ^ : »in a clear ruiining stream far up on the 

 hills between Velbestad and Kirkeboe. Some of the filaments as 

 thick as the feather of a sparrow, wavy, most of them finer and 

 here and there somewhat branched or proliferous. NB. Please notice 

 the habitat: in an algæ-stream, in clear running water«. This cita- 

 tion shows Lyngbye was astonished to find a seawater alga at that 

 height and in freshwater. 



On closer investigation the freshwater specimen proves to be 

 essentially different from the marine one. The two specimens 

 correspond outwardlj^ in being more or less ramified or proliferous, 

 but while the marine specimen has the cells arranged in distinct 

 longitudinal rows even in the thicker branches, the cells of the 

 freshwater specimen are without any arrangement whatever, not 

 only in the thicker branches, but also in the thinner ones. This 

 faet in connection with the thickness of the cell-membrane, the 

 form and size of the cells and of the chromatophors and the more 

 or less strong ramification being the most important characters 

 which help to distinguish the different species (cfr. Ahlner, Agardh, 

 Kjellman, Reinbold and others) prove that Lyngbye's Entero- 

 morpha cannot possibly be E. prolifera. On the contrary I give 

 it as my opinion relying chiefly on Reinbold's paper on the genus 

 Enteromorpha (in Die Chiorophyceen der Kieler Fohrde p. 113) that 

 it must be a form of Enteromorpha compressa (L.) Grev. To the 

 characters already mentioned I may add that the thailus, the thick- 

 ness of which rarely exceeds 1 — 2 millimetres is sometimes branchless 

 and sometimes has branches or prolifications here and there. It is 

 sometimes curly as in Plate IX fig. 3 b. The branches are generally 

 thinner than the main filament and are often more or less prolific. 

 The cells are roundish-polygonal of very varying form and without 

 any arrangement whatever (fig. 3d); they are 4 — ^8;« broad. A trans- 

 verse section (fig. 3 c) of the thailus shows that the outer and inner 

 walls of the cells have all almost the same thickness; the thickness 

 of the cell stratum varies with an average of about 13 /<. 



In a larger stream on Fugl o at a height of 200 m. Ostenfeld 

 collected a small Enteromorpha wdiich corresponds very closely to 

 Lyngbye's specimen or at least it only shows smaller variations. 



^ »i en rindende, klar Bæk hojt oppe paa Fjeldet mellem Velbestad og Kirke- 

 boe. Nogle Traade saa tykke som en Spurvefjer, bølgede, de fleste finere liist og 

 her grenede eller prolifera. NB. Mærk at den fandtes i saadan en Algebæk i det 

 klart rindende Vand«. 



