vi Introduction 



point of the snout to the base of the caudal fin, 

 the fin itself not being included. The depth of 

 the body is from the highest point of the dorsal 

 line to the lowest point of the ventral line, 

 usually from the base of the first dorsal fin to 

 the base of the ventral fin. The expression 

 " head 5 " means that the length of the head is 

 contained five times in the length of the body ; 

 the expression " depth 5 " means that the depth 

 of the body is contained five times in its length; 

 " eye 5 " means that the diameter of the eye is 

 contained five times in the length of the head. 

 In describing the fins the spiny rays are denoted 

 by Roman numerals, and the soft rays by Arabic 

 numerals, and the fins themselves by initials; 

 thus " D. 9 " means that the dorsal fin is single 

 and composed of nine soft rays; " D. IX, 10" 

 means that the single dorsal fin has nine spiny 

 rays and ten soft rays; when separated by a 

 hyphen, as " D. X-12," it means that there are 

 two dorsal fins, the first composed of ten spiny 

 rays and the second of twelve soft ones; "A. Ill, 

 1 1 " means that the anal fin has three spines and 

 eleven soft rays. The expression "scales 7-65-18 " 

 indicates that there are seven rows of scales be- 

 tween the dorsal fin and the lateral line, sixty-five 



