EXTERNAL PARTS OF A FISH 
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includes the salmon (sam'un), trout, bass, whitefish, pike, 
shad, menhaden (men-ha'd’n), cod, mackerel, herring, sar¬ 
dine, etc. Typical bony fishes are the goldfish, perch, and 
sunfish (Figures 59 and 60). 
56. External Parts of a Fish. — The external parts of a 
fish show a well-marked head attached directly to the 
Figure 62.—Diagram of External Parts of a Bass. 
These names are used in describing all fish. 
trunk; a trunk region, the largest part of the body; and 
a tail region which is sometimes as long as the trunk. 
In a bony fish the mouth is at the front end of the head. 
The jaw bones, bearing many small, needle-like teeth, are 
not firmly attached to the skull. The side of the head next 
to the trunk is protected by a piece of 
bone that covers the gills (gill cover or 
operculum, o-per'ku-lum). 
The trunk bears a number of fins. 
Each fin is furnished with several bony 
fin-rays covered by a thin fold of skin. 
On the shoulder and hip regions of the 
trunk, the fins occur in pairs and are 
called the pectoral and pelvic fins. Sev¬ 
eral fins are found that are not in pairs. 
These are the median fins of the trunk. 
The caudal or posterior region of the 
Figure 63. — Scales 
of Fishes. 
