POMATOMIDA. — LVII. 111 
142. ELAGATIS Bennett. (nAaxarn, spindle.) 
289. HE. bipinnulatus (Quoy & Gaimard). Blue, yellow be- 
low; side with 3 longitudinal bluish stripes. Head 32; depth 33. 
D. VI-1, 27-II. A. I[-1, 17-11. L.18. Warm seas, rarely 
N.toL. I. (Meek.) (Lat., bis, two; pinnula, little fin.) 
Famity LVII. POMATOMIDA. (THE BLUE-FISHEs.) 
Closely allied to the Carangide 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 Lacépéde. (aya, opercle; romds, cutting.) 
290. P. saltatrix (L.). Buur-risn. Sxip-sack. Bluish, sil- 
very below; a black blotch at base P.; body robust, somewhat com- 
pressed; P. inserted low, nearly 2in head. Head 31; depth 4. D. 
VIIT—1, 25. A. IL =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.) 
Famity LVUL STROMATEHIDA. (Tue BuTTER-FISHES.) 
This family is also very close to the Carangide, differing chiefly 
in the presence of numerous horny, barbed or hooked teeth in the 
cesophagus, and in the greater number of vertebre (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 having the gill membranes attached to the 
isthmus, while still others have no ventral fins. Genera 5; species 
about 30; of the warm seas. 
4. Ventral fins I, 5, well-developed; premaxillaries protractile; gill openings 
wide; caudal peduncle stout. (Centrolophine.) 
6. Preopercle finely serrate; dorsal spines short and stout; anterior rays of 
D. low; scales moderate... «+ + © +.» « « Letrus, 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. (Stromateine.) 
c. Gill membranes free from isthmus. . . . . . . STROMATEUS, 145. 
144. LEIRUS Lowe. (Aeipés, thin.) 
291. L. perciformis (Mitchill). Biuack Rupprr-risn. Black- 
ish-green everywhere ; eye large; snout blunt. Head 34; depth 23. 
D. VIIT-1, 20. A.III,16. Lat.1.75. L. 12. MainetoN.J., not 
rare N. (Lat., perca, perch; formis, shape.) 
