ARIUS. 171 



oval, greenish blue ; tongue round and fleshy ; up- 

 per jaw slightly produced, and in each a band of 

 crowded teeth ; gill-openings semilunar. The air- 

 bladder is single and heart-shaped; milt double, 

 short, and thick. They are very voracious and take 

 bait readily ; and when hauled on shore, after being 

 caught with the hook, they make a loud gnmting 

 noise. They bite best by night, and are excellent 

 eating." 



Agassiz has dissected this fish, and states, that 

 the opening of the mouth is immediately expanded 

 into a large sac, forming the stomach, of the form 

 of a globe, compressed anteriorly and posteriorly, 

 and which fills nearly the whole upper part of the 

 abdominal cavity. The walls are thickened ; above, 

 on the left side, the csecal appendage arises, and, 

 what is remarkable, the small intestine takes its 

 origin behind nearly the same part. The air-bladder 

 is very large, heart-shaped, and compressed, situate 

 behind the stomach and outside of the peritoneum, 

 — it stretches to the lower third of the abdominal 

 cavity ; the walls are thick, fibrous, and silvery. — 

 Agassiz has remarked a small mucous opening 

 between the scapular processes and pectoral fins, 

 which has not been noticed by Valenciennes, nor 

 is it mentioned by Schomburgk. Future observers 

 should attend to this. 



ARIUS. 



In the genus to which we have referred the next 

 two fishes, we are uncertain, looking at the distinc- 



