the possibility for that wnndcrful ilevelopment met with in the iiioie liigiily cultivated breeds. 

 Three types of caudal tin may be recognized: (I) the single, unjiaircd, vertical form such as 

 occurs in the wild tish and becomes more elongated and lurked under cultivation: (2 I the divided 

 or ])aired iNjie with the two ])aits united alxne, hence with three lubes (one medium, two lateral); 

 (3 I the divided or ])aired form wiili the two parts not united abo\e, hence with four lobes that 

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



Diagram of Three Types of Caudal Fin in Goi.dfi.sh 



culti\atcd indi\iduais of the wakin varietx' : it may be questioned, howe\er. whether such fish, 

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



As Professor Watase has ])ointed out, this di\ision of the caudal hn 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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