20 FISHES OF THE VICINITY OF NEW YORK 



dependent on the waters it inhabits, the amount of food it has had 

 available, and other factors. It is the proportions between the different 

 measurements that are fairly constant within a given species, and which 

 are relied upon for making diagnoses. The larger measurements, as the 

 length of the head and depth of the body, are stated according to the 

 number of times they are contained in the length of the fish, and similarly 

 the smaller measurements, as that of the eye and maxillary, according 

 to the number of times they are contained in the head. The fish's 

 anterior paired fins are known as the pectoral fins. They may be placed 

 on the lower surface, on the side behind the head, or at the throat. The 

 posterior paired fins are the ventral fins. A median fin behind these is 

 the anal fin. One, two or more fins in the mid-line of the back are known 

 respectively, beginning with the anterior one, as the first, second and 

 third dorsal fins. The fin at the end of the tail (which may be pointed, 

 rounded, square or forked in outline, and is occasionally unsymmetrical) 

 is the caudal fin. The number of supporting rays in a particular fin are 

 important in the diagnosis of a fish, as their number is constant within 

 narrow limits of variation, in any one species, just as a normal man has 

 five fingers and toes, no more, no less. These rays may be divided into 

 two classes. First, spines, solid, rigid and sharp-pointed. Second, soft 

 rays, more or less split or branched terminally, jointed and flexible. It 

 is customary to distinguish between the two by using Roman numerals 

 for the spines. Dorsal X, 14 means a dorsal fin with ten spines followed 

 by fourteen soft rays. Dorsal X-14 would mean two entirely separate 

 dorsal fins, the first of spines, the second of soft rays. The lateral line 

 of a fish is a series of pores or markings, usually one on a scale, beginning 

 at the shoulder and ending at the base of the caudal fin. It may be 

 straight or variously curved, complete (if it covers the entire distance) 

 or incomplete, and is sometimes duplicated, or broken in the middle, or 

 lacking altogether. The number of scales, in inverse ratio to their size, 

 is written thus : 5-32-8, which signifies five horizontal rows between the 

 lateral line and base of first dorsal fin, thirty-two more or less obliquely 

 vertical rows crossing the lateral line, and eight horizontal rows between 

 the lateral line and anal fin, or the scales may be counted from lateral 

 line to ventral fin, and so stated. 



There is a regrettable lack of good popular books which will be of 

 service to the amateur in identifying fishes. Almost the only comprehen- 

 sive work, the "Fishes of North and Middle America" by Jordan and 

 Evermann, in four volumes, is too technical and bulky. A comparatively 

 small number of species of fishes occur in one locality. It is hoped that 



