MACKERELS. 459 



also their enemy ; but they seemed to have an instinctive 

 dread of this large fish, and when it approached the ship, 

 would follow it in shoals, and annoy it in the same manner 

 as the smaller birds may be seen to annoy those of a larger 

 and predaceous kind, as the hawk or owl. They are very 

 voracious and miscellaneous feeders. Flying-fish, Calmars, 

 and small shoal-fish are their most natural food; though 

 they do not refuse the animal offal from a ship. Amongst 

 the other food contained in their maw, we have found small 

 Ostracions, File-fish, Sucking-fish, Janthina shells, and pelagic 

 crabs ; in one instance a small Bonita, and in a second a 

 Dolphin eight inches long, and a Paper-nautilus shell con- 

 taining its sepia-tenant. It was often amusiug to watch an 

 Albacore pursuing a Flying-fish, and to mark the precision 

 with which it swam beneath the feeble seronaut, keeping 

 him steadUy in view, and preparing to seize him at the 

 moment of his descent. But this the Flying-fish would often 

 elude by iastantaneously renewing his leap, and not un- 

 frequently escape by extreme agility." 



Pblamys. — The first dorsal continuous, with the spines rather 

 feeble ; from seven to nine finlets behind the dorsal and anal. 

 Scales of the pectoral region forming a corslet. Teeth moderately 

 strong. A longitudinal keel on each side of the tail. 



Five species are known, of which P. sarda is common in 

 the Atlantic and Mediterranean. 



Auxis. — Differing from the preceding two genera in having 

 very small teeth in the jaws only, none on the palate. 



Auxis rochei common in the Atlantic, Mediterranean, and 

 Indian Ocean. 



Cybium. — The first dorsal continuous, with the spines rather 

 feeble ; generally more than seven finlets behind the dorsal and 

 anal. Scales rudimentary or absent. Teeth strong; a longi- 

 tudinal keel on each side of the tail. 



Twelve species from the tropical Atlantic and Indian 



