348 
especially, e. g. the thickness of the thallus, and the number of the 
antherozoids and the carpospores in the antheridium and in the 
sporocarp respectively, as specific distinctions. How far this view, 
which appears to me to be somewhat artificial, is the correct one, 
is rather doubtful, and no definite opinion of it can be formed until 
Hus’s completed work is published. I therefore prefer at present, re¬ 
lying on my above-mentioned observations, to follow Rosen vinge’s 
definition of species, all the more as I had finished the examination 
of my Porphyra- material before receiving Hus’s paper. 
This species generally grows in the sublittoral zone and has 
been found down to a depth of 10—15 fathoms; it is also met 
with near extreme low-water mark especially in rock-pools, and 
grows both on open sea-shore and in sheltered places. Fructifying 
specimens were found in May, June and July. 
This species is very commonly distributed along the Faeroes; as 
mentioned by Simmons (1. c. p. 264) it was first reported from the 
Faeroes by J. Agardh, who, however, does not give the name of the 
discoverer, but it was probably Lyngbye or Rostrup. 
5. P. umbilicalis (L.) J. Ag. Kjellm., N. I., p. 238 (190); Rosenv., 
1. c. p. 830; Ulva umbilicalis Lyngb., Hydrophyt., p. 28. 
f. laciniata (Ag.) Le Jobs, Lisle, p. 99. 
f. umbilicalis (L.) Kleen. 
f. linearis (Grev.) Le Jolis, 1. c. 
Forma laciniata is most commonly met with in somewhat 
sheltered localities, occurring there in the littoral zone near high- 
water mark, e. g. in the narrow part of Sundelaget, where examples, 
some two feet long, are found spreading over stones and gravel. 
Forma umbilicalis is extremely common and is met with abun¬ 
dantly along all the coasts of the Faeroes which are exposed to th^ 
open sea, where it covers the rocks in small, low tufts resembling 
crumbled paper; Wille calls the latter form 0 scopulorum 1 . It 
sometimes extends to a considerable height above sea level. This 
form always grows attached to rocks, but f. laciniata may some¬ 
times be found epiphytic, e. g. on Fucus-species. Lyngbye found 
f. linearis near Kvalbo on Sydero and some of the specimens in 
my collections suggested this form. 
Fructifying specimens were found in May, June, July, October 
and November. 
1 Wille, N.: Bidrag til Algernes physiologiske Anatomi, p. 38. 
