: SEA-FISHERIES LABORATORY. 121 
Fig. 3 represents a section taken from the “ shoulder ” 
region of a large cod: it, too, is made in the transverse plane. 
The epidermis has been lost by rubbing in the course of handling 
the fish in commerce, but a scale is shown. The scales in this 
region are usually buried in the dermis in pockets. The dermis 
_ is mostly a very thick layer of coarse fibrous tissue, divided 
up obscurely into blocks. Beneath it is a layer of much finer 
connective tissue, differentiated into several sub-layers, and 
beneath this again is the musculature (the fibres being rather 
coarser than those of the herring). These various regions or 
_ layers of “ skin”’ and superficial tissues need not be described 
more minutely (they are really very complex and variable in 
different fishes). What the figures are intended to show is 
_ the general situation of the oil which is present in the“ flesh ” 
of the herring; the contrast between Summer and Winter 
herrings ; and that between fat-rich fishes, like the Clupeoids, 
and fat-poor fishes, like the Gadoids. 
Fat also occurs in the massive form, in the herring, as de- 
posits in the peritoneum and mesenteries, and sometimes 
it is very abundant there, so that dissection becomes a“* messy ” 
_ task on account of the liquid nature of the fat. It occurs, of 
course, in the liver also, but the latter organ is not very large 
in Clupeoid fishes. Both liver fat and massive peritoneal fat 
_ may differ chemically from that which may be expressed from 
the flesh—at least such seems to be indicated by mere exam- 
ination: little has, of course, been done to distinguish the 
differences. | 
In fat-poor fishes, such as the Gadoids, the liver is the great 
store place. Both in these fishes, and also in Skates and Rays, 
the liver undergoes very marked seasonal changes, becoming 
both larger and richer in oil in the warm months. In these 
- fishes the condition of the liver is always noted by fishermen 
(it is sometimes eaten) and regarded as indicative of the dietetic 
value of the flesh. More than half the weight of cod liver may 
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