On the Caudal and Anal Fins of 

 Gold-fishes. 



By 



S. Walase, Nôéakushi. 

 Of llie Sapporo Agricultural College and of the Imperial University. 



With Plates XVIII— XX. 



As is well known, the fins of fishes have been put under two 

 categories, the paired and the unpaired. The former includes the 

 pectoral and ventral fins, and the latter, the dorsal, caudal and anal 

 fins. On this point, however, there is a remarkable deviation in our 

 gold-fish. Here we find not only the pectoral and ventral fins, but 

 also the anal and caudal fins distinctly paired in many individuals. 

 In such cases, the fish presents a series of four paired appendages, 

 a circumstance that has no parallel in all known natural species of 

 Vertebrates. 



That our gold-fish is an abnormal form which has been 

 cultivated is an acknowledged fact, and many of its characters are 

 no doubt mere products of artificial selection and devoid of all 

 morphological significance, but the paired state of the caudal and 

 anal fins is, in my view, of great interest when considered in 

 connection with the problem on the nature of the paired and un- 

 paired fins. 



In the present article are embodied the results of my researches 

 into this curious condition in the caudal and anal fins of the gold-fish. 



