PROCEEDINGS OF THE SOCIETY. 
811 
fresh in memory, were quite inadequate after a lapse of time to give the 
detailed information required for such a catalogue as they had in 
contemplation. 
Mr. W. West’s paper “ On New British Freshwater Algfe ” was read 
in abstract by Mr. A. W. Bennett, who said that this description of 
new British freshwater algm was an important addition to their know- 
ledge of these organisms. The author was one of the best of the few 
students of this subject, and he had already added much to their infor- 
mation in this direction. The illustrations with which the paper was 
accompanied were very admirably executed by Mr. West and by his son 
Mr. George West, both of whom wete remarkably skilled in drawing. 
The thanks of the Society were, on the motion of the President, 
unanimously voted to Mr. West for his paper, and to Mr. Bennett for 
reading it to the meeting. 
Mr. T. F. Smith, who had been announced to read a paper “ On the 
Ultimate Structure of Pleurosigma angulatum ,” was unable to do so owing 
to some misunderstanding as to the provision of a lantern for the exhibi- 
tion of the photographs with which he had intended to illustrate the 
subject. 
Prof. Bell read a paper by Mr. G. Sandeman on “ A Parasitic 
Disease in Flounders,” as follows : — 
There are often found on our coasts flounders having small round 
swellings under the skin, occurring singly or grouped in larger masses 
which have been described under the name of multiple tumours. In the 
Scottish Fishery Board’s Reports,* Prof. M‘Intosh has written on this 
disease, and in the eleventh report I have given a short account of the 
microscopical features of the “ tumours,” with drawings of various 
appearances of them; 
The tumours have in every respect the appearance of eggs deposited 
immediately beneath the skin of the fish. When occurring on a trans- 
parent fin beneath the rays, they are seen to be perfectly regular and 
opaque spheres ; and when under the skin on another part of the body, 
they give rise to a low smooth projection of the skin which is apparently 
unbroken and of its normal colour. If there is little pigment on the 
skin over the egg, the latter shows through a clear white colour. The 
eggs are from 1 to 1 • 5 mm. in diameter. On one fish there may be 
many such single eggs distributed quite irregularly, but more often they 
are grouped in masses consisting of from two to a hundred or more 
elements. In the smaller groups the eggs usually lie side by side, 
assuming a polygonal form, owing to mutual pressure. They cause a 
low projection of the skin which sinks slightly between the individual ova. 
But when very many are present in one mass, the large tumour which 
is formed projects considerably from the body, and is sometimes even a 
pedunculated or finger-shaped formation, the skin over it being still 
normal and showing through it the closely packed elements. While the 
single eggs are more frequently found on the dorsal, ventral, and caudal 
fins, and under the skin of the body on the upper side, the large masses 
* iii. p. 66 ; iv. p. 214. 
3 K 
1893. 
