Embryology and Growth of Fishes 



151 



Monstrosities among Fishes. — Monstrosities are rare among 

 fishes in a state of nature. Two-headed young are frequenth' 

 seen at salmon-hatcheries, and other abnormally divided or 

 united young are not infrequent. Among domesticated species 

 monstrosities are not infrequent, and sometimes, as in the gold- 



FiG. 117. — Mon.strous Goldfish (bred in Japan), Carassius auraius (LinnaBus). 



(After Giinther.) 



fish, these have been perpetuated to become distinct breeds or 

 races. Goldfishes with telescopic eyes and fantastic fins, and 

 with the green coloration changed to orange, are reared in Japan, 

 and are often seen in other countries. The carp has also been 

 largely modified, the changes taking place chiefly in the scales. 

 Some are naked (leather-carp), others (mirror-carp) have a few 

 large scales arranged in series. 



