THE FISHES OF NEW JERSEY. 127 



f. Maxillary barbel minute, not quite terminal. se;motii,us 



ff. Maxillary barbel absent. LEuciscus 



ee. Postventral region tranchant, scales not passing over its edge ; 



anal basis long. brama 



dd. Teeth in main row 4-4, lesser row often absent. 



g. No maxillary barbels; upper jaw protractile. 



NOTROPIS 



gg. Maxillary with a small barbel near its tip. 



h. Premaxillaries not protractile ; teeth 2, 4-4, 2. 



RHINICHTHYS 



hh. Premaxillaries protractile; scales 35 to 55; teeth 



4-4, or I, 4-4, I or o, lesser row with never more 



than I. HYEOPSis 



cc. ExoGLossiN^. Lower jaw singularly formed, dentary bones parallel, 



united their whole length. ExoGLOSSUM 



Genus Hybognathus Agassiz. 

 The Gudgeons. 



Hybognathus nuchalis regius (Girard). 



(Frontispiece — Part II.) 



Gudgeon. Silvery Minnow. 



Head 4^^ ; depth 4 ; D. 11, 7, i ; A. iii, 7, i ; scales 37 in 

 lateral line to base of caudal, 3 more on latter; 6 scales obliquely 

 back from origin of dorsal to lateral line; 4 scales between 

 origin of ventral and lateral line; snout 3^^^ in head; eye 3^^; 

 maxillary 4 ; interorbital space 2^ ; pectoral i ; ventral i % ; 

 least depth of caudal peduncle i •% ; pharyngeal teeth 4 — 4. Body 

 elongate, somewhat compressed and slender. Head rather short, 

 blunt. Snout blunt, protruding a little beyond mandible. Eye 

 small. Maxillary not reaching eye. Interorbital space broad, 

 convex. Gill-rakers few, short, fleshy. Scales large, uniform 

 in size. Lateral line continuous, slightly decurved. Intestines 

 long, more than 7 times length of body. Peritoneum black. 

 Dorsal inserted nearer tip of snout than base of caudal. Anal 

 inserted behind tip of depressed dorsal. Caudal deeply forked, 

 lobes pointed. Pectoral about 3/5 of space to ventral. Ventral 

 inserted behind origin of dorsal and reaching about ^/^ of space 

 to anal. Color mostly silvery, back pale translucent olive. Fins 

 pale, dorsal and caudal a trifle dusted. Iris silvery. Length 

 4% inches. Trenton. 



