ACANTHOPTERYGII 677 



Fam. 1. Carangidae. Praemaxillaries more or less pro- 

 tractile. Vertebrae 24 to 26; ribs behind the parapophyses ; 

 epipleurals on the parapophyses, rarely on the ribs. 1 Body 

 covered with small scales, or naked, often with enlarged scutes 

 on each side of the body or of the tail ; dorsal spines few, or 

 slender or rudimentary ; a more or less developed spine adnate 

 to the soft portion of the anal, often preceded by a pair of spines 

 separated from the rest of the fin. Pseudobranchiae usually 

 present. Inhabitants of the seas of the temperate and tropical 

 regions, many of the species having a very wide range. About 

 150 species are known. 



Principal recent genera : Caranx, Chloroscombrus, Selene, 

 Mene, Apolectus, Nematistius, Seriola, Seriolichthys, Naucrates, 

 Trachynotus, Zalocys, Lichia, Paropsis, Chorinemus. Species of 

 Caranx, Mene, and Seriola have been described from the Eocene 

 and Miocene of Europe, in which occur also the fossil genera 

 named Vomeropsis, Arckaeus, Carangopsis, Carangodes, Ductor, 

 and Semiophorus. 



The family is represented on our coasts by the common 

 Horse-Mackerel, Caranx trachurus. The young of this species 

 keep together in small bands in the neighbourhood of medusae, 

 under which they seek shelter when distiirbed. The Pilot-Fish, 

 Naucrates ductor, is a truly pelagic fish of wide distribution, 

 which occasionally appears on our coasts, accompanying large 

 sharks and ships. Much has been written on the marvellous 

 habits of this little fish, which is said to lead the shark like 

 a pilot, directing it to its food, in exchange for which services 

 the pilot enjoys protection from the fear which the proximity of 

 its formidable companion inspires to its enemies among other 

 carnivorous fishes, and an abundance of food from the shark's 

 excrements. 2 



Fam. 2. Rhachicentridae. Praemaxillaries slightly pro- 

 tractile. Vertebrae 25 (11 + 14), without well - developed 

 parapophyses ; ribs and epipleurals inserted close together on the 

 centra. Body covered with very small scales ; a series of short 

 isolated dorsal spines ; soft dorsal and anal long ; pectorals 



1 Naucrates. In this genus most of the epipleurals of the praecaudal region are 

 inserted on the ribs, but the hinder ones are on the centra. 



2 Cf. GeofFroy, Ann. du Mus. ix. 1807, p. 473 ; F. J. F. Meyen, Eeisc um die 

 Erde, i. p. 56 (1834). 



