FISHES 



355 



Photograph by E. R. Sanborn, N . Y. Zoiil. Soc. 

 FIG. 137. Carp (Cyprinus carpio). 



streams of the eastern United States. The 

 goldfish belongs to this family ; in its wild form 

 it is dark, the gold variety existing only in a 

 state of domestication. The case recalls that 

 of the canary, the wild form of which is a dull- 

 green bird. These conspicuous and beautiful 

 forms have arisen as variations, and have been 

 conserved by man, who admired them. The 

 Japanese have also obtained in a similar manner 

 many strange and grotesque forms of goldfish, 

 which would have no chance for success in the 

 struggle for existence in the wild state. 



(d) Haplomi. The pikes (Esocides) and the killi- Pikes and 

 fishes (Pceciliidce) are common fresh-water 

 forms. Some of the latter are excessively 

 abundant in certain localities, and are very im- 

 portant as destroyers of mosquito larvae. The 

 pikes will be recognized by the elongate snout, 



