214 



BRANCH CHORDATA 



are mostly tropical and marine. The true eels, genus Anguilla, which 

 crawl " in the mud and ooze of brackish and fresh waters of most regions, 

 are absent on the Pacific Coast of America."' They are very voracious 

 and are especially fond of shrimp and crayfish, which they find by over- 

 turning stones. They will also devour dead fish. They sometimes go 

 considerable distances in the damp vegetation on land, thus avoiding water- 

 falls and other obstructions. The females are larger and lighter colored 

 than the males and have smaller eyes and higher fins. In the spring the 

 eggs are deposited in the sea. It is said the young ascend rivers and after 

 two or three years return to the sea to spawn. A Brazilian eel {Gymno'tus) 

 is electric, having two pairs of batteries in the ventral portion of its long 

 tail. " A metamorphosis is known only in the eel-like fishes, the larvae 

 of which are flat, transparent forms, with colorless blood, enormous tails, 

 and very small trunks. The larva? normally occur in the sea at a depth 

 of several hundred fathoms. "^ 



^\^''.,'^- ^■^IMJ^<M^■^<^■^ 



Fig. 177. — Winter flounder (Pseu'do})lciiro>u'c'tes america' nus) . (After 

 Goode.) 



The blind fishes (Amblyop'sidoe) of Mammoth Cave are colorless and 

 translucent. They have rudimentary eyes, but have lost their sight 

 through disuse for many generations. They have no lateral line. Their 

 knowledge of danger comes through the hearing, which is very acute. The 

 head is very flat and the mouth is directed upward, as food is scarce near 

 the bottom. They come to the surface to feed, but at the slightest noise 

 dart beneath stones at the bottom. 



Sub-order Anacan'thini includes the cod, haddock, whiting, as well as the 

 flat fishes — soles, turbots, flounders, halibuts, etc. There are nearly a 

 hundred species of codfish. Some reach a length of 4 or 5 feet and weigh 

 100 pounds. The female lays nine or ten millions of eggs in a single season. 

 They rise to the surface of the sea and hatch in about twenty days. 

 There is one fresh-water codfish. 



The haddock resembles the cod in appearance and habits. 



' Jordan. "^ 



2 Kingsley's translation of Hert wig's " Zoology." 



