NOTE 



In our descriptions of species, we have attempted to bring the prin- 

 cipal comparative measurements first. Tlie expressions " head 4," or 

 "depth 4" mean tliat tlie length of the head in the one case, or the 

 greatest depth of the body in the other, is contained 4 times in the 

 length of the fish measured from the tip of the snout to the end of the 

 last caudal vertebra, the caudal fin being not included. The size of the 

 eye and the length of snout and other head parts are compared with the 

 length of the side of the head, unless otherwise stated ; thus " eye 5 " 

 means that the horizontal diameter of the eye is ^ the length of the 

 head. "Scales 5-64-7" means that there are 5 rows of scales between 

 the base of the dorsal fin and the lateral line (the scale in the lateral 

 line excluded), 64 oblique transverse series crossing the lateral line, and 

 7 horizontal series between the lateral line and the base of the anal or 

 the vent. When the number of pores in the lateral line is fewer than 

 the number of scales in it, we have usually indicated the fact. 



The fin formula are usually shortened as much as possible; thus D. 

 10," " D. IV, 9," or " D. VIII-13," means that in the first case the fish has 

 a single dorsal fin of 10 soft or articulated rays; in the second case, a 

 single dorsal fin of 4 spines and 9 soft rays; and the last indicates a fish 

 with 2 dorsal fins, the first composed of 8 spines and the second of 13 raj's. 



Spines are alwaj^s indicated in roman letters. 



The abbreviations for the other fin formuhe are similarly explained. 



The measurements given in the text are intended to apply to the aver- 

 age of mature fishes. Young fishes usually have the depth less, the head 

 and eye larger, and the mouth smaller, than adult examples of the same 

 species. 



Descriptions not taken from specimens, or at least not verified by us, 

 are credited to the author from whom they have been copied. 



" Eu." after the account of any species indicates that it is found in 

 Europe. 



The names of the localities from which the types of the species were 

 obtained, are printed in anticpie old style type in connection with the 

 synonymy of each species. 



When the type specimens are in the United States National Museum, 

 we have given the numbers which they bear on the register of that 

 institution. 



An atlas, containing anatomical figures and illustrations of many of 

 the more important species, is now in preparation and will appear upon 

 the completion of the second volume of the present work. 



(IX) 



