the Marine Algcv of the Firth of Forth. 443 



limits of llie estuary seawards, may be looked upon as the 

 NifophyUum area. 



Above this the Dclcsserice (D. alata and D. sinuosa) and 

 specimens of Plocamium coccineum were procured more 

 abundantly than any others — Ddesseria alata being the 

 most commonly observed, and Plocamium coccineum more 

 abundantly than Delesseria sinuosa. Many specimens of 

 all these have been noted entangled in deep-sea fishing 

 lines. Fruit has been found in all of them ; and as there 

 is reason to believe that they here form a fairly distinct 

 characteristic, this may be designated the Delesseria- 

 Plocamium area. Its extent, though probably reaching 

 into the NifophyUum area, may be set down between the 

 limits of low water and 28 fathoms, being best represented 

 at depths extending between 16-24 fathoms. At mt'ny 

 parts of the estuary specimens of all of these forms occur 

 at low-water mark, e.g., Inchcolm, Inchkeith, Fidra, Dun- 

 bar, Fifeness, &c., and very commonly, e.g., on living 

 crustacean carapaces even at from 12-16 fathoms. Many 

 of the largest specimens, especially of Delesseria sinuosa and 

 Plocamium coccineum, have been found among drift weed, 

 and must, from their size, have come from deep water. 

 The same also applies to several specimens of Delesseria 

 sanguinea which were observed. 



The Laminarian area characterised by the presence of 

 large specimens of L. clousfoni, L. saccharina, and Alaria 

 esculenta, is most distinctly defined at a depth of from 3 to 

 16 fathoms. In the clear deep water to the east of the 

 May Island this zone is seen to the best advantage. In 

 tidal pools specimens of all the representative species are 

 common, but their growth becomes markedly smaller as 

 their upper limit is approached. On detached stipes of 

 L. cloustoni, Melohesia laminarioi, along with other epi- 

 phytic Algse (e.g., Phodymenia palmata, Ptilota j^l^^nosa, 

 Polysiphonia parasitica, Delesseria sinuosa, Dasya coccinea, 

 &c.), have been observed. The most perfectly developed 

 specimens of the characteristic plants of this area seem to 

 occur at a depth of about 15 fathoms. Well-formed speci- 

 mens, however, often showing the characteristic stages of 

 the renewal of the frond at the end of the stipes, occur off 

 Inchcolm in a depth of from 3 to 4 fathoms. 



