148 CONTRIBUTIONS TO NOETH AMERICAN ICHTHYOLOGY IV. 



dd. Upper jaw protractile ; teetli not molar, 

 e. Teeth two-rowed, 2 teeth in the lesser row. 

 /. Lateral line complete. 



g. Teeth subcorneal, scarcely hooked, sharp-edged, wide apart, the long 

 limb of the jiharyugeal bone elongate. 



Ptychochilus, 100. 



gg. Teeth compressed, close-set, strongly hooked ; the pharyngeal bone of 



the usual form. 



A. Caudal peduncle slender and elongate, the caudal fin widely forked, 



its basal rudiments much develoxied; scales very small ; 



head depressed Gila, lol. 



hli. Caudal peduncle stout; basal rudiments of caudal little developed. 



Squalius, 102. 



ff. Lateral line incomplete Phoxixus, 103. 



ee. Teeth one-i"owed. 



- Lateral line complete. 



g. Mouth of moderate size Leucos, 104. 



(jg. Mouth extremely small Opsopceodus, 105. 



— Lateral line incomplete ; teeth serrate TrychzERODON, 106. 



JJ. Abdomen behind ventral fins compressed to an edge, 

 the scales not passing over it ; anal basis usually elou- 

 gate ; dorsal jjosterior. 

 i. Abdomen in front of ventrals rounded ; anal basis rather long. 

 j. Teeth 5-5, with grinding surface and serrate edges. 



NOTEMIGONUS, 107. 



/ jj. Teeth 2, 5-5, 2, entire, without grinding surface-ALBURNUS, 108. 



* * Dorsal fin short, posterior, with a strong spine, composed of two, the posterior re- 

 ceived into a longitudinal groove of the anterior ; inner 

 border of the ventral fins adherent to the body ; teeth 

 hooked, without grinding surface, in two I'ows. (Phujo- 

 2)teriiia\) 

 I. Body with small scales ; teeth 2, 4-4, 2 ; no barbels. 



Lepidomeda, 109. 

 U. Body scaleless. 



w. Maxillary without barbel ; teeth 1, 4-4, 1 Meda, 110. 



vim. Maxillary with a barbel ; teeth 2, 5-4, 2. 



Plagopterus, 111. 

 *** Dorsal fin elongate ; dorsal and anal fins each preceded by a serrated spine ; 

 scales large; teeth molar; siiecies introduced. {Cg- 

 imnince..) 



7). Barbels 4 ; teeth 1, 1, 3-3, 1, 1 Cyprinus. 



tin. Barbels none; teeth 4-4 Carassius. 



■71.— CAinPOSTOMA Agassiz. 



Stone rollers. 



(Agassiz, Amer. Journ. Sci. Arts, 1855, 218: type BitUlus anomalus Raf.) 



Body moderately elongate, little compressed. Mouth normal, the 

 jaws with thick lips aud rudiment of a hard sheath. Premaxillaries 

 protractile; no barbel. Teeth 4-1:, or 1, 4-4, 0, with oblique grinding 

 surface and bat a slight hook on one or two teeth. Air-bladder sus- 



