88 



FISH GALLERY. 



Moon- 

 eye. 



Notop- 

 terus. 



a large, pendulous yolk-sac (see 1162, Cabinet-case 29, and 

 fig. 49). 



The Moon-eye, Hyodon tergisus, 244, of the fresh waters of 

 North America east of the Rocky Mountains, constitutes a special 

 family by itself, the Hyodontidae. It is a silvery fish about 

 12 to 18 inches long, with a lai'ge mouth with strong, sharp 

 teeth, and some particularly large teeth on the tongue. There 

 are teeth on the parasphenoid bone, a primitive feature which is 

 common to this fish and Elops, Megalops, Albula, Arapaima, 

 Osteoglossum, Notopterus, and most Mormyridse, but which occurs 

 in no other living Teleostean fishes. 



The species of Notopterus, constituting the family Notopteridse, 

 are strange-looking fishes with a much compressed body, a short- 



Fig. 49. — Young Gymnarchus m'loticus, showing the large 



yolk-sack (y.s.) and the long external gills (e.g.). 

 (From Bridge, Canib. Nat. Hist., vii, 1904, after Budgett.) 



based dorsal fin and a very extensive anal fin, which is continuous 

 with the caudal fin. They are fresh-water or brackish-water 

 fishes found in the marshes and lakes of Africa, India and the 

 Malay Peninsula, and feeding on worms and insects. One of 

 the largest species is Notopterus chitala of India (245), which 

 grows to three or four feet in length ; another well-known species 

 is Notopterus kapirat (246), also from India and the Malay 

 district. The scales are thin and cycloid, and extend over the 



