96 
Proceedings of the Royal Society of Edinburgh. [Sess. 
of the genera Cocconeis, Gomphonema, Diatoma, etc. A handful of 
this Cladophora was taken from Loch Fifty and floated at the top 
of a tall vessel of water. In the course of several days a considerable 
deposit of pure diatom frustules had fallen from the Cladophora and 
collected upon the bottom of the vessel. 
Cladophora glomerata, Kiltz. Very abundant in some lochs of Areas 
IY. and VI., covering stones and rocks from the margin to 7 feet deep. 
Mougeotia sp. Sometimes very abundant in I. and IY. 
Zygogonium ericetorum, De Bary. “ I.,” IY. Often very abundant in 
water near the shores of the hill lochs. 
Zygnema Yaucherii, Ag. I., II.” It is also very frequent in lochs 
of Areas IY. and YI. 
Porphyridium cruentum, Nag. YI. Wet mud at Barhapple Loch, ex- 
posed through drought, was in places coloured red by this organism. 
Gloeotrichia Pisum, Thur. YI. Occurred in such extreme abundance 
as a plankton organism in Soulseat L. that the water in some of 
the little creeks was of the consistency of liquid mud. 
Anabaena circinalis, Rabenh. YII. The water of Kinghorn Loch in 
places had the appearance of pale green paint, due to the vast 
quantity of this organism. It is frequently common in lowland 
lochs. The relationship between the presence of this plant and the 
death of certain fish, particularly perch, requires further elucidation. 
I found numbers of dead perch around Kinghorn Loch. 
Melosira granulata, Ralfs. YI. Occurs as a plankton organism in 
White Loch, Castle-Kennedy, in such abundance that the discolora- 
tion of the water (p. 143) is in part due to it. 
Dickieia and similar gelatinous Diatomaceae. “ I.,” IY. Sometimes 
abundant at the margins of the hill lochs. Other diatoms, of course, 
abound everywhere. 
I have frequently found submersed plants of the higher orders 
injured by the luxuriant growth of filamentous Algae. In Lochs 
Skerrow and Grennoch, for example, quantities of Scapania undulata 
were in a defunct condition through being overgrown with Ulothrix 
aequalis, Batrachospermum vagum, Binuclearia tatrana, etc. 
The following comparative table has been arranged in order to show 
at a glance the most conspicuous and abundant plants (i.e. those forming 
more or less definite associations) of peaty and non-peaty lochs, together with 
the positions they usually occupy therein. The plants have been divided 
into seven groups, and those in each group are so arranged that the species 
