LEPIDOSTEUS 



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This order contains two survivors of a very ancient 

 group of fishes. Lepidosteiis 

 was abundant in Europe dur- 

 ing the Eocene and Miocene, i 

 and representatives of Amia t. 

 persisted until the Lower Mio- 

 cene period. 



Four species of Lepidosteus, 

 the bony pike or gar pike, are ^, VXWiMKH !T'P. 

 found now in the rivers and c. 

 lakes of North and Central 

 America, and one in China. The 

 jaws are greatly elongated, form- 

 ing a kind of " beak." The 

 body is covered with rows of 

 shining " ganoid " scales. The 

 skeleton is bony, the backbone 

 especially so : there the verte- 

 bral centra are opisthocoelous, 



a remarkable occurrence in a U/ XVWi^d a- «j .a 

 fish. The spiracle is absent 

 and there is a physostomatous 

 air-bladder, which seems to 

 function in some degree as a 

 lung. Pyloric caeca are present, 

 and there is a trace of a spiral 

 valve in the intestine. Lepidos- 

 teus is a voracious carnivorous 

 fish, living largely on other fishes 

 and frequenting the deeper >\\^^ 

 waters. In the late spring it 

 visits the shallows of the lakes 

 to spawn. The eggs are some- 

 what oval, 3 mm. in diameter. 

 Segmentation is meroblastic. 

 The newly hatched larvae are very 

 unlike the adult in shape, with a 

 short thick head with glandular 

 pre-oral cement-organs. After 

 the yolk-sac is absorbed , they feed 

 on insect larvae (mosquitoes), and later take to a fish diet 



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