HORSE-MACKERELS. 



441 



Vcntrals thoracic, sometimes rudimentary or entirely absent. 

 No prominent papilla near the vent. Gill-opening wide. Ten 

 abdominal and fourteen caudal vertebrce. 



Inhabitants of tropical and temperate seas. Carnivorons. 

 They appear first in cretaceons formations, where they are 

 represented by Flatax and some Caranx-like genera ( Vomer 

 and Aipiehthys from the chalk of Comen in Istria). They are 



Fig. 195. — Semioplionis velitans. 



more numerous in various Tertiary formations, especially in 

 the strata of Monte Bolca, where sonJe still existing genera 



