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HISTORY AND ANATOMY OF THE GOLDFISH 
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The ordinary goldfish has two sets of horizontal paired fins, the 
anterior paired or pectoral fins, Fig. 2, connected with the clavicles and 
the skull immediately behind the gills, and the posterior paired or ventral 
fins inserted on the abdominal surface below and to the rear of the pectorals 

FIG. 2—Skeleton of the Common Goldfish 
and articulated to the posterior visceral arches and the pubic bone. The 
single median or dorsa/ fin is interspaced with the upper interspinous bones; 
the single ana/ fin with the lower interspinious bones, and the tail or caudal 
fin set vertically at the extremity of the spine, articulated so that it is flex- 
ible in all directions. The rays of all the fins are branched, increasing in _ 
number towards their extremities. The spinous and soft rays of the paired 
fins correspond with the bones of the limbs of other animals, one of their 
functions being to maintain the balance of the fish. Retrograde motion 
is principally affected by the pectoral fins which also direct the course of 
the fish by acting as propellers, further serving as adjuncts to the respi- 
ratory system in changing the water at the gills. The ventral fins act as 
a break in checking the forward motion in addition to aiding in the retro- 
grade movement. ‘The dorsal and anal fins balance the body, and as rud- 
ders prevent zigzag or rocking motion, while the caudal fin is the principal 
means of locomotion, and also, together with the anal fin, aids in steering 
the fish. 
All the fins are organs of motion, but it is by the caudal fin that the 
fish is impelled forward. If the movement is to be swift, it is strongly 
bent to the right and left, while a gentle forward motion is effected by an 
undulating movement, the lobes and rays of the caudal fin, acting like the 
blades of a screw or an oar in sculling. If the fish wishes to move 
towards the left, it gives a stroke of the tail to the right, the right pectoral 
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