■)44 TRANSACTIONS AND PlIOCEEDINGS OF THE [Sess. i.vn. 



Supplementary Notes ox the Marine Algae of the 

 Orkney Islands. ]5y George Wm. Traill. 



(AVith Zincograpli.) 



(Read at the :\[ectiii- of tlie Society on Feliruary 11, 1892.) 



While on a few weeks' visit to South Pionaldsay, in 

 ()rkney, last summer, seeing that the ]\Iarine Algae of the 

 island had been comparatively little studied, I devoted my 

 attention to the subject in the hope of being successful in 

 finding new species to add to the (Orkney list. 



The island is seven and a half miles long, by about 

 three in average breadth, and is deeply intersected with 

 l)ays. 



A coast of this extent might be thought likely to yield 

 fair results ; but, from my having been unable to dredge, 

 and having thus had to confine myself almost exclusively 

 to the littoral Algae, the results are unfortunately not so 

 good as I might otherwise have been able to show, 



I found above llTj species. These being, as a rule, 

 very similar to the littoral Algae enumerated in my 

 Orkney list, I sliall mention only those which are of 

 special interest, including several not hitherto recorded. 



Calothrix jmlvinata (Mert.), Ag. — At the west of St. 

 Margaret's Hope, near " The Needle " ; chiefly on the sides 

 of grassy tufts covered by the sea at higli tides only. Now 

 first recorded as an Orkney species. 



Calothrix scopulonnn. (Web. and Mohr.), Ag. — At Kirk- 

 ness in abundance, on smooth, flat rocks near high-water 

 mark. Now first recordtnl as an Orkney species. 



Frasiula siipltata, Sulir. — Occurs sparingly at the east 

 of Harrabrough Head, on rocks and large stones in shaded 

 places exposed to the north, at about the high-water mark 

 of neap tides. The only other Orkney locality recorded is 

 Scapa l)ay, where I found it in 1(S<S7, but it is scarce there 

 also. 



Jjiijops'iH pltniiusd (Huds.), y\g. — At Kirkness, very fine 

 in pools at about half-tide level; also at the east of 

 Harrabrough Head, but not so large. 



Vauchcria sphaerosjjora, Nordst. ; / i/cjiuIjkc, Nordst. ; f. 

 (lioica, Nordst. — At the Oyce of Quindiy ; at the west side 



