4:4:4: Mf Eattiay on the Distribution of 



Desmarestia aculeafa has been repeatedly observed en- 

 tangled in deep-sea nets, and is of by no means uncommon 

 occurrence as drift weed in the crannies on the eastern 

 side of the May Island. I have not been able definitely to 

 assign to it any given depth at this place, but from the 

 circumstance of its occurring in nets working at from 16 

 to 26 fathoms, its habitat is probably at the lower limit of 

 the present area. Two specimens of Desmarestia viridis 

 were found in similar depths as those of D. aculeata from 

 this neighbourhood. 



Within the limits of the Laminarian area numerous 

 other species have been noted — the most characteristic 

 of these are CaUithamnion lAumula, Phyllophora brodicei, 

 Cystoclonium purpurasce7is, Delesseria alata (small or not 

 of more than medium size), CaUithamnion tumeric Phyllo- 

 phora ruhens, Chylocladia clavellosa, Lithothamnion poly- 

 morphum, Delesseria sanguinea, Cruoria pelita, Odonthalia 

 dentata^ &c. 



Occupying a situation encroaching upon the upper limits 

 of the last-noted area, the Phyllophorce must be looked upon 

 as sufficiently characteristic of another area, having as 

 typical species Phyllophora hrodimi. Its highest develop- 

 ment may be regarded as extending between 2 and 10 

 fathoms. Phyllophora hrodicei and P. ruhens are both 

 common. Corallina officinalis has been found as the upper 

 reaches of the area are approached. Polysip)honia hyssoides 

 occurs towards its lower margin. Phyllophora memhrani- 

 folia and Odonthalia dentata are not unfrequent, the latter 

 often attaining a length of 5 inches ; and Melobesia calcarea 

 is in some places {eg., south-west of Inchkeith) so abundant 

 as to be quite a well-marked characteristic of its middle 

 part. Rhodymenia pahnata attains a moderate size here, 

 and Chorda Jilum, which is not uncommon in many places, 

 maybe looked upon as characteristic. Chorda tomentosa is 

 also present. Fuci (e.g., F. serratus, F. platycarpus) grow 

 on rocks towards the upper limits, but their peculiar posi- 

 tion must be looked upon as somewhat higher up, Furcel- 

 laria fastigiata and Polyides rotundus can also be seen 

 at such depths on the eastern side of the May Island. 

 Ceramium ruhrum is not unfrequent, as well as several 

 Callithamnia (e.g., C. iurneri, C. p)lumula, &c.), off Inch- 



