142 The Apodes, or Eel-like Fishes 



Hay has recently found, in an example from the Cretaceous 

 of Mount Lebanon, remains of distinct ventral fins. These 

 traits seem to indicate an almost perfect transition from the 

 Isospondyli to the Archencheli. 



One family may be recognized at present, Urenchelyidcc. 



The earliest known eel, Urenchelys avus, occurs in the upper 

 Cretaceous at Mount Lebanon. It represents the family Uren- 

 dielyidaz, apparently allied to the Anguillida, but having a 

 separate caudal fin. Its teeth are small, conical, blunt, in 

 many series. There are more than 100 vertebrae, the last 

 expanded in a hypural. Pectorals present. Scales rudiment- 

 ary; dorsal arising at the occiput. Branchiostegals slender, 

 not curved around the opercle. Urenchelys anglicus is another 

 species, found in the chalk of England. 



Suborder Enchelycephali. - The suborder Enchelycephali (ey- 

 XeJivs, eel; /ce0aA/;, head) contains the typical eels, in which 

 the shoulder-girdle is free from the skull, the palatopterygoid 

 arch relatively complete, the premaxillaries wanting or rudi- 

 mentary, the ethmoid and vomer coalesced, forming the front 

 of the upper jaw, the maxillaries lateral, and the cranium with 

 a single condyle. In most of the species pectoral fins are present, 

 and the cranium lacks the combined degradation and speciali- 

 zation shown by the morays (Colocephali). 



Family Anguillidae. The most primitive existing family is that 

 of the typical eels, Anguillidce, which have rudimentary scales 

 oblong in form, and set separately in groups at right angles with 

 one another. These fishes are found in the fresh and brackish 

 waters of all parts of the world, excepting the Pacific coast of 

 North America and the islands of the Pacific. In the upper Great 

 Lakes and the upper Mississippi they are also absent unless intro- 

 duced. The species usually spawn in the sea and ascend the 

 rivers to feed. But some individuals certainly spawn in fresh 

 water, and none go far into the sea, or where the water is entirely 

 salt. The young eels sometimes ascend the brooks near the sea 

 in incredible numbers, constituting what is known in England 

 as "eel-fairs." They will pass through wet grass to surmount 

 ordinary obstacles. Niagara Falls they cannot pass, and 

 according to Professor Baird "in the spring and summer the 

 visitor who enters under the sheet of water at the foot of the 



