864 Bulletin 4.7, United States National Museum. 



Mouth rather large, with lateral cleft ; premaxillary not protractile ; 

 maxillary without supplemental bone ; jaws with sharp teeth, large or, 

 small. Vomer and palatines toothed or not. Preopercle entire ; opercle 

 unarmed. In the very young the preopercle is armed with radiating 

 spines, which are later absorbed and lost. Gill openings very wide, the 

 membranes not united, free from the isthmus. Gill rakers usually long. 

 Pseudobranchise present, large. Gills 4, a slit behind the fourth. Bran- 

 chiostegals 7. Dorsal fins 2, the first of rather weak spines, depressible 

 in a groove, the second similar to the anal; the elevated anterior lobe 

 always distinct ; anal spines weak ; last rays of dorsal and anal detached 

 and separate, forming in each case a series of finlets ; caudal peduncle 

 extremely slender, keeled, the caudal lobes abruptly diverging, falcate, 

 the fin adapted for rapid motion; ventral fins well developed, thoracic, 

 I, 5. Vertebrae in greater number than in Carangidcv, the number rang- 

 ing from 31 to 66. First upper pharyngeal present, without teeth ; second 

 with teeth; third and fourth coossified, with teeth ; lower pharyngeals 

 separate. Stomach sac-shaped. Pyloric coeca numerous. Air bladder 

 small, sometimes absent. Coloration metallic, often brilliant, the pre- 

 vailing shade steel blue. Genera about 12 ; species about 60. Fishes of 

 the high seas, many of them cosmopolitan, and all having a wide range; 

 most of them are valued as food-fishes, the flesh being firm and oily, but 

 sometimes coarse. (Scombridce, part, Giinther, Cat., n, 349-373.) 



SCOMBRIN^E : 



a. Caudal peduncle without median keel on each side; dorsal fins well separated, the inter- 

 space being less than half length of head; spinous dorsal short, of 9 to 12 spines; 

 body scaly; vertebrae normally formed; slender teeth on vomer and palatines; maxil- 

 lary entirely covered by preorbital; a fleshy lobe on each side of lower jaw near its 

 junction with maxillary; corselet very small or obsolete; gill rakers long, slender, and 

 numerous; pectorals inserted high, on level of eye; vertebrae 14 + 17 = 31. 



SCOMBER, 388. 

 aa. Caudal peduncle with median keel; a small keel above and one below this; pectoral 



usually inserted below eye. 

 SARDINE : 

 6. Dorsal spines 10 to 16; gills normal, the laminae not forming a network; teeth entire. 



c. Body scaleless, excepting about the lateral line and corselet; abdominal vertebrae with 

 their lower foramina enlarged, and a portion between the vertebrae proper and the 

 haemapophyscs developed in the form of a network or trellis. 



d. Dorsals well separated, the interspace more than half head; corselet well devel- 

 oped; teeth small, some present on vomer, none on palatines; gill rakers long, 

 slender, and numerous; pectorals rather high; vertebra? 39. Auxis, 389. 



dd. Dorsals contiguous, the interspace more than 5 in head; palatine teeth villiform; 



pectorals low. 



e. Vomer toothless; dorsal spines 15 or 16; vertebrae 38. GYMNOSARDA, 390. 



cc. Body wholly covered with small scales, those on the corselet and lateral line sometimes 

 larger; dorsal spines 14 to 26; vertebrae normally formed, not as in Auxis and Gym- 

 nosarda. 



f. Teeth of jaws slender, subconical, little, if at all, compressed; gill rakers numer- 

 ous; corselet distinct; pectorals inserted low. 



</. Vomer and palatines with villiform or sand-like teeth; body robust, not com- 

 pressed; vertebras 39 to 41. 



/(. Pectoral short, not reaching much beyond tip of the moderate ventral; 



size enormous. THUNNUS, 391. 



hh. Pectoral very long, ribbon-shaped, reaching much beyond front of anal; 



size moderate, GEKMO, 392. 



