POMATOMID^. — LVII. Ill 



142. ELAGATIS Bennett. (fjKaKd-rn, spindle.) 



289. E. bipinnulatus (Quoy & Gaimard). Blue, yellow be- 

 low ; side with 3 longitudinal bluish stripes. Head 3| ; depth 3f . 

 D. VI- 1, 27-11. A. II -1, 17-11. L. 18. Warm seas, rarely 

 N. to L. I. (Meek.) (Lat., bis, two; pinnula, little fin.) 



Family LVII. POMATOMIDJE. (The Blue-fishes.) 



Closely allied to the Carangidce but with the scales larger and 

 weakly ctenoid. Mouth large, oblique, with very strong, compressed, 

 unequal teeth ; premaxillaries protractile ; caudal peduncle stout, 

 the fin forked, with broad lobes; preopercle serrate; lateral line 

 unarmed. First dorsal of about 8 fragile spines ; second D. and A. 

 long ; anal spines minute. A single species, in most warm seas. 



143. POMATOMUS Lacepede. (napa, opercle ; to/xos, cutting.) 



290. P. saltatrix (L.). Blue-fish. Skip-jack. Bluish, sil- 

 very below ; a black blotch at base P. ; body robust, somewhat com- 

 pressed ; P. inserted low, nearly 2 in head. Head 3£ ; depth 4. D. 

 VIII- 1,25. A. 11-1,26. Lat. 1. 95. L. 3 feet. Warm seas, 

 common on our Atlantic coast ; an excellent and gamy fish, but very 

 destructive to other species. (Lat , leaper.) 



Family LVIII. STROMATEID^E. (The Butter-fishes.) 



This family is also very close to the Carangidce, differing chiefly 

 in the presence of numerous horny, barbed or hooked teeth in the 

 oesophagus, and in the greater number of vertebra; (30 or more). 

 There are no free anal spines, and the spinous D. is very much re- 

 duced or even wanting. Some of the species differ from other 

 mackerel-like fishes in bavinp; the grill membranes attached to the 

 isthmus, while still others have no ventral fins. Genera 5 ; species 

 about 30 ; of the warm seas. 



a. Ventral fins I, 5, well-developed; premaxillaries protractile; gill openings 

 wide; caudal peduncle stout. (Centrolopkirxe.) 



b. Preopercle finely serrate; dorsal spines short and stout; anterior rays of 



D. low; scales moderate Leirus, 144. 



aa. Ventrals minute or absent; premaxillaries not protractile; caudal pe- 

 duncle slender; the fin widely forked ; opercles entire; scales minute; 

 spinous D. almost obsolete. (Stromateinw.) 



c. Gill membranes free from isthmus Stromateus, 145. 



144. LEIRUS Lowe. (Xtipos, thin.) 



291. L. perciformia (Mitchill). Black Rudder-fish. Black- 

 ish-green everywhere ; eye large ; snout blunt. Head 3J ; depth 2\. 

 D. VII -1,20. A. Ill, 16. Lat. 1.75. L. 12. Maine to N. J., not 

 rare N. (Lat., perca, perch ; formis, shape.) 



