SIGNS, ABBREVIATIONS, ETC. 7 



Lat. Z.=Lateral line, i.e., the number of scales contained in its 

 course. When the lateral line is obsolete, " lat. 1." signifies 

 the number of scales in a row from the head to the base of 

 the caudal fin. Thus, "lat. 1. 36" means that there are 36 

 scales in a row along the sides from the head to the caudal. 

 In all cases the number of rays or scales, as given in the 

 descriptions, is intended to represent a fair average, and a vari- 

 ation of one-sixth, or' even more, in either direction need not 

 surprise the student. Generally the spines and scales are more 

 constant in their numbers than the soft rays, and the fewer of 

 either, the less variable. 



Depth in length=The greatest depth of the body as contained in 



the distance along the side from the snout to the base of the 



caudal. 

 Head in length=The distance from the snout along the cheeks to 



the extremity of the opercle, as contained in the distance 



from the snout to the base of the caudal. 

 Eye in head=Its longitudinal diameter as contained in the length 



of the side of the head. 



As above stated, these measurements, as given in the descrip- 

 tions, are intended to be the average of living adults, and must be 

 applied to young specimens or preserved ones with caution. 



Young fishes are always much more elongated than adults, and 

 the eye is proportionally much larger. 



A fin is said to be " long" when it has a long base, or is many- 

 rayed. A "high" fin is one in which the individual rays are 

 elongated. 



