the possibility for that wonderful development met with in the more highly cultivated breeds. 

 Three types of caudal fin may be recognized: (1) the single, unpaired, vertical form such as 

 occurs in the wild fish and becomes more elongated and forked under cultivation; (2) the divided 

 or paired type with the two parts united above, hence with three lobes (one medium, two lateral) ; 

 (3) the divided or paired form with the two parts not united above, hence with four lobes that 

 are more or less horizontal when spread. The second and third types are found in the most highly 



DIAGRAM OF THREE TYPES OF CAUDAL FIN IN GOLDFISH 



cultivated individuals of the wakin variety; it may be questioned, however, whether such fish, 

 departing so much from the simple breed, are entitled to be called by this name. 



As Professor Watase has pointed out, this division of the caudal fin is not a mere splitting of 

 the superficial parts, but depends on an actual bilateral separation of the deep-seated bony elements 

 from which the fin arises. Professor Ryder has expressed the view that the double-tailed goldfish 

 were produced originally by the orientals shaking or otherwise disturbing the eggs at the period of 

 development when the blastoderm had spread over about a third of the yolk. This treatment of the 



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