of Edinburgh, Session 1885-86. 
845 
3. On some Algoid Lake-Balls found in South Uist. 
By G. W. W. Barclay, F.B.S.E. (Plate XXX.) 
In August of last year I was in South Uist on an angling expe- 
dition, and, while fishing one of the lochs on the island, my attention 
was drawn to some very remarkable balls that were lying in great 
numbers at the bottom. I examined a good many of these, and 
found that they were composed of innumerable algal filaments so 
intertwined and matted together as to form an outer covering of 
an almost felt-like consistency, which could, however, be torn open 
without difficulty. This outer coating varied (speaking very roughly) 
from about a twentieth to two-twentieths of an inch in thickness, 
or even more, and the interior of the balls consisted, so far as the 
naked eye could see, only of mud. The microscope, of course, tells 
a different story. 
I made a number of inquiries at the time with a view to discover- 
ing if possible the nature and origin of these balls, but beyond the 
fact that they were well known to have existed from time imme- 
morial in this loch (and, it was confidently asserted, in no other 
loch on the island), I could ascertain nothing about them. I 
brought away some of the balls with me, and, failing to find any 
mention of them in any books on the Hebrides to which I could 
gain access, I wrote to the principal inhabitants of the island, and 
to any one else whom I thought likely to be able to assist me in my 
efforts to discover what the balls were and how they originated — but 
without result. I was not at that time aware that lake-balls of this 
kind are found in several European countries, and, after making 
that discovery, I should scarcely have thought them sufficiently 
curious to justify my taking up even a very little of the time of the 
Society, but that some of my friends who had seen them and who 
are learned in botanical matters seemed to consider them rarities, 
and to think that some account of them might be interesting. I 
venture, therefore, to offer a very brief description of the balls (of 
which I have placed a number on the table for inspection), and to 
give an account of the locality in which they were found. 
A microscopic examination of the balls shows that they are com- 
posed of a filamentous alga, Cladophora glomerata, a variety of 
