60 



Frederikshavn in some years only in small quantities, while in others it forms 

 extensive growths especially on the outer side of the south mole, as in the be- 

 ginning of August 1902. In the Little Belt it completely disappears in summer, at 

 all events in certain years (e. g. 1901), while in spring it is often abundant and 

 luxuriant. In March 1894 it was so well developed there, that I have never found 

 it better developed on the Danish shores; the threads attained a length of 14 — 15 cm 

 and were above thick and curled (fig. 3). In April 1904 I searched for it in vain at 

 the same place. This is the most southern locality known on the Danish shores. 



Localities. Ns: Th3'bor0n , groin No. 58. — Sk: Hirshals, on the mole and on a boulder on 

 the shore, oljserved in the months April to August, may occur abundantl}' still in Jul}'. Has also been 

 found growing on Phyllitis zuslerifolia (fig. 4). Greatest length of the threads observed here ca. 7 cm. — 

 lit': Harbour of Lemvig (?) ; Thisted; Glyngore. — Kn: Harbour of Skagen ; Busserev by Frederikshavn 

 (April and July); harbour of Frederikshavn. — Ke: Harbour of Gilleleje, Febr. and May, ca. 1 cm long. — 

 LI): Harbour of 1^'redericia (Hofm. Hang, !) ; harbour of Middelfart, stone-slope west of the harbour, March 

 and April, Kongebro. 



Bangia pumila Are.sch. (Dakbishiri:, Ueber Bangia pumila Aresch., eine ende- 

 mische Alge der ostlichen Ostsee. Wiss. Meeresuntersuchungen , N. F. 3.Bd., Abt. 

 Kiel 1898, S. 25) which according to Dahbishihe is readily distinguished from B. 

 fnsco-purpiirea as well as from the fresh- water B. atro-piirpiirea, and which, as far 

 as known, is endemic in the Baltic, has not been met with hitherto in the Danish 

 shores, though I have sought for it, particularly on the shores of Bornholm. It 

 differs from B. fnsco-purpLirca in particular in that the articulation of the frond is 

 still distinct in the older frond, which is divided by longitudinal walls, and through 

 smaller cystocarps. As it has been found at Swinemiinde and at Dantzig, there is 

 reason to believe that it may also be found on the Danish Baltic coasts. 



According to Kvi.ix (1907 p. 109), however, this species has been found by 

 Ahkschoug not in the Baltic but "in den innersten Buchlen von Goteborg". This 

 author regards it as being not a distinct species but probably only feebly developed 

 specimens of B. fnsco-purpiirea. 



Porphyra Agardh. 

 1. Porphyra iimbilicalis (L.) J. Ag. (Plate I and II fig. 1 — 3.) 



J. Agardh (1883) p. 66. 



P. laciniata (Lightf. ) Ag.; Thuret in Le Jolis Liste des Alg. mar. de Cherbourg 186-1, p. 99, Janczewski, 

 litudes anat. sur les Porphyra. Ann. sc. nat. V*^ ser., t. 17 1873, p. 241, pi. 19 fig. 25—26; Thuret et 

 Bornet, Etudes phj'cologiques, 1878, pi. 31, p. 58. 



f. linearis (Grev.) Harv. 



P. linearis Greville, Algte britannicae 1830 p. 170 tab. 18; Kiitzing Tabuhe phycologic;e XIX tab. 79; J. 



Agardh, I.e. p. 71; Le Jolis Algues marines de Cherbourg No. 9() ; Kylin (1907) j). 111. 

 Ulva purpurea /J, elunyuta Lyngb. Hydr. p. 29. 



oulgaris forma, Harvej' Phycologia Britannica ])1. 211, tig. 2 — 3; Thuret in Le Jolis Liste [). 99. 

 P. hiemalis Kylin, (1907) p. 112 Taf. 3 fig. 2. 



L viilgdris (Ag.) Thur. in Le Jol. Liste p. 99. 

 Uh'u purpurea Both Catalecta 1 p. 209, Lyngb. Hydr. p. 29. 



