Addenda. 
Fam. Bangiaceæ. 
2. Erythrotrichia reflexa (Crouan) Thuret in herb. 
Hauck, Meeresalg. Deutschl. u. Oesterr. 1884, p.22; G. Hamel, Floridées de France. Bangiales. Revue 
Algologique, Vol. I, 1925, p. 288. 
Bangia reflexa Crouan, Algues mar. du Finistère. III, N. 394, 1852. 
Porphyra reflexa Crouan, Florule du Finistère 1867, p. 132, pl. 10, fig. 73. 
In July 1923 I found in the harbour of Frederikshavn a small Erythrotrichia 
which agreed with E. reflexa (Crouan) by its short curved filaments attenuated at 
both ends. The same species was found again in the following 
years in several places in the Northern Kattegat. 
Only little has been added to our knowledge of E. reflexa 
since it was described in 1852 by the brothers Crouan upon 
specimens from Brest. Hauck recorded the species from the 
Adriatic Sea but, according to Hamer (Il. c. p. 289), the plant 
which Hauck has communicated under this name is not E. reflexa 
but E. obscura. HAMEL records the localities known on the coast 
of France, and gives some dimensions for the specimens of CRoUAN: 
thickness at base 10 w, in the middle 35 w and near the top 15 w. 
The Danish specimens, which I have examined in a living 
state and well preserved, show larger dimensions than those 
given by Hauer which are 
= @ = in accordance with my 
en) CS oO observations on examining 
@ So CD the original specimens of Fig. 611. 
©) () = Crouanandspecimensfrom Erythrotrichia reflexa 
> : = from Tonneberg Ban- 
N at Biarritz. 5 
O 5 ®) BORNET collected atB ABU ke, Northern Kattegat, 
a 0 ©) The lower part of the frond 19 m, July. The fila- 
/ isting 9 ingle row ment is by exception 
° Q Con ay consisting CARS ngl not attenuated at the 
OVA DE B SES Cc of cells showed a thickness top: 
g IG ON of 17—35 u, and the middle- 
most part a thickness of 32—63 4, most often 
FÉES about 46 w. The plants may reach a length of 
Erythrotrichia reflexa. B, young plant. A et C, 
basal parts of plants. 350 :1. 
5 mm but are usually shorter, about 2 mm 
