48. AMBLYOPSIDyE. 323 



slender. Pedtoaeuin silvery. Head 3f in length 5 depth about 4^. D. 

 11 ; A. 8 ; Lat. 1. 50. L. G inches. Spawns in spring. Delaware River 

 to Kansas and northward ; abundant in the Great Lakes. One of our 

 most remarkable fishes. 



(Agassiz, Lake Superior, 1850, 283; Giintlicr, vi, 207: 1 Percopsis hammondi'* Gill, 

 Proc. Acad, Nat. Sci. Pliila. 18G4, 151.) 



Oeder N.-IIAPLOMI. 



[The Saplomous Fishes.) 



1^0 precoracoid arch. Parietal bones separated by the supraoccipital. 

 A symplectic. Opercular bones present. Anterior vertebrae unaltered. 

 Pharyngeal bones distinct, the superior directed forwards, three or four 

 in number, the inferior not falciform. No interclavicles. Mouth with 

 teeth. Air-bladder with a pneumatic duct. Ventral fins abdominal, 

 rarely wanting; pectoral fins jjlaced low; dorsal fin more or less pos- 

 terior, usually without spines. Head and body usually with cycloid 

 scales. No adipose fin. Species chiefly inhabiting fresh water. («-/«?;?, 

 simple; w/xo^, shoulder; in allusion to the want of the precoracoid arch.) 



(Phifsostomi part (families Esocidce, Umhridce, Cyprinodontidw and Heteropygii) Giin- 

 thcr, vi, vii.) 



ANALYSIS OF FAMILIES OF HAPLOMI. 



a. Margin of upper jaw formed by premaxillaries alone; ovovivi parous. 



h. Vent jugular; premaxillaries scarcely protractile Amblyopsid^, 48. 



Ih. Vent abdominal ; premaxillaries freely protractile Cyprixodontidje, 49. 



aa. Margin of upper jaw formed laterally' by the maxillaries; premaxillaries not pro- 

 tractile. 



c. Jaws not produced ; teetb villiform, equal Umbrid^e, 50. 



cc. Jaws produced ; teeth cardiform, imequal Esocid.e, 51. 



Family XLVIIL— AMBLYOPSIDiE. 



{The Blind-fishes.) 



Body moderately elongate, compressed behind. Head long, de- 

 pressed. Mouth rather large, the lower jaw projecting ; premaxilla- 

 ries long, scarcely protractile, forming the entire margin of the upper 

 jaw. Jaws and palatines with bands of slender villiform teeth. Bran- 

 chiostegals about 0. Gill-rakers very short. Pseudobranchi;x3 con- 

 cealed. Gill-membranes more or less completely joined to the isthmus. 



* Head larger, 3| in length, exclusive of caudal ; dorsal higher, the longest ray 4 J 

 in length; an;il higher, longest ray fi in length; pectoral equals height of dorsal; 

 ventral 5J in length, reaching vent, which is nearer snout than margin of caudal fin. 

 Kansas. {Gill.) 



