284 Field Museum of Natural History — Zoology, Vol. VII. 



This fish is generally distributed over central and northern Europe 

 and Siberia. It was introduced for aquariums, and is now thriving 

 in the lagoons in the parks of Chicago. 



Carassius auratus (Linnaeus). Gold Fish. 



Head 3X; depth 2%; D. iii, 18; A. iii, 7; scales 26. 



Body robust, compressed; scales larger than in preceding species; 

 dorsal and anal each with strong spines, serrated behind; lateral line 

 complete. 



Color as in preceding species. 



Length about 10 inches. 



Native of China and Japan. Introduced for aquariums, but it 

 is now abundant in the lagoons in the parks in Chicago. In breeding 

 many varieties have been produced. 



Order ApodeS. 



The Eels. 



Body very elongate; vertebrae numerous, the anterior ones dis- 

 tinct and without Weberian ossicles ; ventral fins absent ; fins without 

 spines; skeleton bony; mesocoracoid absent. 



Family Aiig'iiillidse. 



The True Eels. 



Body elongate, snake-like; covered with fine embedded scales; 

 head without scales; vertebrae numerous, the anterior ones not mod- 

 ified; fins without spines; dorsal and anal fins continuous with the 

 caudal; tail isocercal; gill openings small; mouth terminal, the jaws 

 about equal; teeth on jaws, vomer, and palatines; air bladder with 

 open duct. 



Genus Aiiguilla Shaw. 



Eels. 



Body elongate, slightly compressed; head large; mouth large, 

 jaws about equal; dorsal caudal and anal fins connected. 



