eggs of other fishes is known to result in various forms of double monsters double heads, partly 

 double bodies, double tails, etc. most of which necessarily die early. In the case of goldfish presum- 

 ably produced in this way, those with double tails were most likely to reach maturity because of the 

 least vital parts involved. "These being selected and bred," to quote Ryder, "would in all probability 

 hand onward the tendency to reproduce the double tail, a tendency which could become very fixed 

 and characteristic if judicious selection were maintained by interested fanciers and breeders." 



The wakin is the largest of the goldfishes. Its normal length is 6 to 10 inches, and it 

 exceptionally reaches 16 inches. It is also the hardiest, the easiest to breed and transport, and the 

 most extensively cultivated. 



When the wakin escapes from cultivation and becomes established in open waters, it reverts 

 after a few generations to the color and form of the original wild fish, all the highly colored 

 individuals disappearing. This has been well illustrated in the Potomac River, where the escape 

 of cultivated fish from the government ponds in Washington has resulted in stocking the river 

 with goldfish that are not recognized as such by fishermen and fish dealers, and are sold in the 

 markets under the very inappropriate name of "sand perch." 



