FISHES 143 



Suborder 10. Heterostomata. — The flat-fish. Bones of the head 

 unsymmetrical, both eyes being on the same side; anus near the head; 

 pseudobranchiae present; dorsal fin extending the length of the body; 

 anal fin similar but shorter; body much compressed, the side without an 

 eye being usually colorless and kept lowermost; young individuals 

 symmetrical : 2 families, all marine, one species in fresh water. 



Family Soleidae. — The soles. Body oval in outline; cranium much 

 twisted, the mouth very small; teeth rudimentary or wanting: 150 

 species. 



Achirus Lacepede. Eyes and color on right side; scales well devel- 

 oped, ctenoid; eyes separated by a bony ridge; pectoral fins minute or 

 wanting: numerous species. 



A . fasciatus Lac. Length 200 mm.; head 4; depth 1.8; color dusky 

 olive, mottled with 8 dark, narrow, vertical stripes; rays of dorsal fin 

 50 to 55; anal 37 to 46; scales 66 to 75; origin of dorsal fin at tip of 

 snout: Cape Ann to Texas, ascending rivers; common. 



