20 P. A. ØYEN. M.-N. Kl. 
Strongylocentrotus droebachiensis Mix. 
Pomatoceros tricuspis Put. 
Protula borealis Sars. 
Balanus porcatus pa Costa, Darw. This species is very variable, 
and sometimes it has a rather rugged shape. I had a very good oppor- 
tunity to study the variation of this species, as I succeeded in picking 
up no less than 134 complete specimens and 219 somewhat imperfect 
ones of the full-grown normal type and 628 juvenile specimens. It may 
have a more stunted appearance or a more elongated shape. Beside the 
above mentioned specimens, eight complete ones were found belonging 
to a series of elongated shape. In some cases it has an appearance that 
make one strongly feel the probability of the hybrid connection with 
Balanus crenatus. Broken specimens of Balanus are very numerous, 
Balanus crenatus Bruc., Darw. was very numerous and variable, 
occurring either in forma typica or in more elongated shapes. I suc- 
ceeded in picking up no less than 490 complete specimens, and broken 
ones were quite superfluons. Of course, I had a good opportunity to 
study the variation of different kind and of all growths. And it was of 
a great interest to me that in August 1909 I had an opportunity to 
attend the Darwinian exhibition *to commemorate the centenary of his 
birth’! as I near Kilebu found five complete specimens and numerous 
broken ones of the same elongated variety, which was also represented 
in the collection of Darwin's original specimens. A number of speci- 
mens ranging as Balanus crenatus we may be justified in regarding as 
hybrids with Balanus porcatus as mentioned above. Clusters, groups, 
or single individuals of Balanus may often be seen attached to mollus- 
can shells, for instance, Pecten islandicus. 
Verruca stroemia Mitr. Darw. occurred in forma typica. 
In some places stones are covered with a grey or yellowish ma- 
terial of calcareous origin that migth in some cases perhaps be due to 
Lithothamnion. . 
In order to get a more general view we are to tabularize the results 
of the biometrical analysis and we shall then see that the main part of 
the shell-bank is composed of only some few species: Anomia ephip- 
pium, Pecten islandicus, Mytilus edulis, Mytilus modiolus, Macoma cal- 
caria, Mya truncata, Saxicava pholadis, Natica clausa, and Buccinum sp., 
together with Balanus porcatus and Balanus crenatus. 
1 British Museum (Natural History) Special Guide No. 4. London 1900. 
