112 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
situated on the side of the fish behind the operculum. The 
tumour measures 74 by 61 by 59 mm. along its three 
principal diameters. It weighs 110 grams, after having 
been preserved in 70 per cent. alcohol for some months. 
It is soft, and easily deformed by slight pressure, but there 
is no softening or break-down of the tissue in its interior. 
Along one side, in the plane of the principal diameter 
there is a deep sulcus, almost dividing the growth into two 
parts. What this means, or how it has been produced I 
cannot say, unless the tumour may have been growing 
round the operculum of the fish, so that the latter was 
situated in the cleft. The growth was capsulated, and on 
slitting open the investment it dropped out. It is yellow- 
white in colour, and quite opaque, without any trace of 
the slight translucency noted with regard to the last 
specimen. 
Sections were made, and these showed that the 
structure was very simple. The whole growth consists of 
fibrous connective tissue (see fig. 3, Pl. V), loosely 
arranged, and showing an obscure lamination concentric 
with the outer surface. The fibres are very delicate, like 
those present in areolar tissue, but running in relatively 
long, wavy bundles, between which are fairly wide inter- 
spaces. For the most part this is the only tissue present. 
The tumour is vascular, but not richly so; and round the 
blood-vessels the connective tissue fibres run concen- 
trically, and there are small round cells in these places. 
Occasionally there are nests of these connective tissue 
cells, but such structures are few in number. 
The growth belongs, obviously, to the class of 
encapsulated non-pedunculated fibrous tumours or 
‘“wens.’’ It is benign in nature, and probably did not 
injuriously affect the health or condition of the fish, 
though it must have given the latter a rather repulsive 
