THE ADIPOSE LOBE OP THE PELVIC PIN OP THE SALJION. 713 
extremity {V.) lias become flattened, the dorso-lateral bordei- 
is markedly longer than the ventro-Iateral, the latter is 
deeply furrowed. There is no epidermis; the outer border is, 
as before, formed by the membrana basale {M. h.) Im- 
mediately below the surface occur several layers of closely 
packed connective-tissue fibres. These run parallel to the 
surface which they subtend, and are very definitely defined ; 
they are not shown in fig. 5, which was drawn from a hand- 
cut section; they appear, however, in fig. 6. There is a large 
accumulation of fat-globules {Ft.) in the central area; they 
appear a.s a band of orange running parallel with the 
accessory scale in sections stained with Sudan III. In 
addition a small clump appears in the central area on the 
outer side of the scale, where the latter makes a small bend 
away from the outer border of the lobe. 
A few pigment-cells {Pig.) occur in the outer wall. The 
accessory scale {Sc. a.) is seen a.s a narrow strip of hyaline 
substance, running approximately parallel to the outer border 
of the lobe throughout the length of the latter. In sections 
from the same region of other salmon, there is sometimes a 
knotted swelling in that part of the accessory scale which 
lies within the broad portion of the lobe; it is more usual, 
howevei’, to find this swelling nearer the distal end ; such a 
condition is realised in fig. 6. 
As the distal end is approached, the outline of the lobe 
and the shape of the accessory scale vary considerably in 
different salmon.i This is not surpi-ising’ in an organ of sucli 
adventitious nature. The most constant and, moreover, the 
most striking feature of the distal area of the lobe is the 
presence of a patch of well-defined stratified epithelium. 
This epithelium, which is depicted in Text-fig. 2 (1), and 
under higher magnification in fig. 7 {Ep.), corresponds Avith 
the normal mucous epithelium of fishes; that is to say, it con- 
sists of round cells on the surface, passing into oval cells, 
and finally into palissade cells, the latter standing on a Avell- 
' So far as I have observed they are always similar in both the adipose 
lobes of the same fish. 
