738 



Fiircellaria fdstigiala, Chondriis crispiis, Laurencia pinnatifida, Halo- 

 saccion rameiilaceiun. Cernminm riibriim, Chætomorpha Melagonium, 

 Porplujra ininiald and P. lencosticla, Alaria esculentn, Lamiuaria digi- 

 tata and L. saccharina, especially f. PhijlUtis, si)ecies of Delesseria, etc. 

 and in general several algæ wliich otherwise grow only in the sub- 

 littoral region. 



Thus il is evidenl, that a great many differenl species may be 

 found in the pools; especially in the low lying basins. To show 

 how rich in species such pools may be, we may mention that, 

 according to Rattray (67, p. 428) Traill has found 67 different 

 species in a relatively small littoral pool in the Firth of Fortil. 



It may be pointed out that it is peculiar to the algæ-vegetation 

 growing in the pools that the different species often grow irregularly 

 mingled with each other. This is surely due to the absence of tides. 

 In larger littoral pools one may however see the algæ forming very 

 distinct belts; various green algæ uppermost: Enteromorpha, Clado- 

 phora etc, and farther down Pohjsiphonia , Rhodomela, Chondriis, 

 Delesseria etc. In a littoral pool above the highest water mark, but 

 with clean water, En/e/'omoryj/ja intestinalis for instance was found along 

 the edge, next to that a helt of Cladophora riipestris and Cladophora 

 sericea, below that a dense matting of Corallina with small Mono- 

 stronm fiiscnm, and lastly Laurencia pinnatifida in great quantities. 



This distribution is most clearly seen in large, deep pools 

 found so far up in the littoral region that the waves can reach 

 them only in slormy weather. In the summer in calm weather, 

 the uppermost layer of water will turn brackish by the supply of 

 rain and the different lavers of water will be distinctly indicated by 

 the vegetation. 



In his report of the littoral rock pools on the west coast of Nor- 

 way, Boye (6, p. 26) also calls our attention to the great differences 

 in the vegetation which correspond with the different heights at 

 which the basins are found. He moreover emphasizes that only 

 Enteromorpha intestinalis is found at the greatest height. He also 

 says that Hansteen's »U/yaceen-formation« (38, p. 346) probably be- 

 longs in part to this vegetation. 



Si m mons, who does not give any special report of the vege- 

 tation of littoral pools, says (78, p. 253), when speaking of the »Co- 

 ra//ma-formation«, Ihat the Corallina may abundantly cover the bot- 

 tom of such pools. 



