THE ADIPOSE LOBE OF THE PELVIC FIN OP THE SALMON. 709 
side is adaxial and simply represents the result of the gradual 
rounding-off of the angular adaxial surface which has been 
noted at the proximal end. The outer vertical surface is grey 
in colour and firm in textui’e ; the two inner surfaces, namely 
the dorso-latex'al which faces the body-wall, and the ventro- 
lateral which faces the upper surface of the outermost fin-ray, 
are white in colour and soft to the touch. When at rest, the 
two inner siu’faces of the lobe are closely apposed to the 
surfaces of the fish which they respectively subtend; as a 
result of this the soft ventro-lateral surface is grooved in its 
posterior half owing to the pressure of the fin-skeleton. 
The lobe is equally well developed in specimens of both 
sexes, and, as far as one can judge fi’om the comparatively 
few specimens which I have been able to examine, it further 
appears that the size of the lobe is not altered during the 
seasonal movements of the fish. Specimens were examined 
in the pink of condition, fresh from the sea, and others which 
had spawned and were, in some cases, infected with fungus, 
but neither the regular outline of the lobe nor its consistency 
appeared to differ in any degree ; this is worthy of note, as it 
is well known that the body-scales of the salmon undergo a 
very marked disintegration at their margins, known as the 
spawning-mark, after the sexual products have been shed. 
Only in one unfortunate fish, which had long been suffering 
from an unsightly wound,^ was the adipose lobe, on either side, 
reduced to a mere stump. The following measurements are 
from a male salmon weighing 22 1 lb., 100 cm. in length, 
52 cm. in girth, taken in the Wye, and will serve to convey 
an idea of the normal proportions of the adipose lobe : 
Length of outer margin of pelvic fin . lO'O cm. 
„ inner „ „ . . 5'5 „ 
Breadth of distal ,, ,, . . 6'0 „ 
„ proximal „ ,, . . 3’0 ,, 
Length of adipose lobe .... 4'0 ,, 
Breadth ,, (at base) . . 0'7 „ 
' A hole about an inch in diameter piercing the body-wall and enter 
ing the abdominal cavity in the anal region. 
