INTRODUCTION. 
XXXI 
Gunther’s Catalogue of the Fishes of the British Museum, the first five volumes, 1859-1865; 
Dumeril, Ichthyologic generate, volume the first, 1865. 
Before commencing the individual descriptions, a few explanatory remarks are requisite on 
the mode adopted in taking measurements, &c. 
Roman figures are employed to designate the number of the brancliiostegous rays : also the 
finlets, as in the Caranx Rottleri, &c., or elongated free rays, as appendages to the pectoral fins 
in the Polynemi; an exceptional case being in the Bregmaceros Macclellandi, in which it is im¬ 
possible to give the various portions of the fins distinctly without using these figures. 
O signifies an adipose fin. 
In counting the number of rays, when two arise from one interneural or interhcemal spine, as 
frequently takes place in the last of the dorsal and anal fins, they are reckoned as one, a plan 
sanctioned by high authorities, but open to objection and not adopted by Dr. Bleeker. In the 
caudal fin the small outer rays are not included. The horizontal procumbent spine which exists in 
many genera before the base of the dorsal fin is not included in the formulary, neither is the short 
vertical bone before the dorsal spine in many of the siluroids. 
By L. 1. is meant the number of pierced scales, extending from the shoulder bones to the 
base of the caudal fin. By L. r. tiie numbers of rows of scales passing downwards from the back 
to the lateral line along its whole extent. By L. tr. the number of scales in a row passing down¬ 
wards from the origin of the dorsal fin to the lateral line, and between the lateral line and the 
abdomen. In speaking of the lateral line of mullets, the term is only used for convenience of 
description, as it is absent. 
By the total length, is meant that included between the end of the snout and the centre of 
the termination of the caudal fin, unless otherwise stated, as in the Fistularia serrata, in which 
the two central rays are produced into long filaments. 
By the length of the head, is commonly meant from the anterior end of the jaws when closed 
to the posterior extremity of the bony opercle; to this several exceptions exist, as in the Alutarius 
leevis, in which the eye and much of the skull is behind that situation, whilst in the Hemiramphus 
the lower jaw is extended in the form of a beak far beyond the mouth. 
By the length of the snout, is meant the distance between the anterior margin of the orbit 
and the centre of the intermaxillaries, unless otherwise stated, as in the Genus Belone. 
By the length of the base of a fin, as the dorsal, is meant the distance between the base of its 
foremost to that of its hindermost spine or ray, except in those genera which have a procumbent 
horizontal spine before them, which is not included. 
By the length of a fin is meant its extreme length even when it is prolonged, thus in the 
Poly acanthus cupanus the pectoral is given to the end of its filament. 
By the height of a fin is meant the length of its longest spine or ray, unless otherwise 
expressed. 
