XXII ACANTHOPTERYGII O77 
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.’ Body 
covered with small scales, or naked, often with enlarged gcutes 
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 
Caranz, Mene, and Seriola have been described from the Eocene 
and Miocene of Europe, in which occur also the fossil genera 
named Vomeropsis, Archaeus, Carangopsis, Carangodes, Ductor, 
and Semtophorus. 
The family is represented on our coasts by the common 
Horse-Mackerel, Caranz trachurus. The young of this species 
keep together in small bands in the neighbourhood of medusae, 
under which they seek shelter when disturbed. 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.” 
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, Reise wm die 
Erde, i. p. 56 (1834). 
