48. AMBLYOPSID.E. 323 



slender. Peritoneum silvery. Head 3 in length ; depth about 4 J. D. 

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

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

 most remarkable fishes. 



(Agassiz, Lake Superior, 1850, 283; Giinther, vi, 207: ? Percopsis hammondi * Gill, 

 Proc. Acad. Nat. Sci. Pliila. 1864, 151.) 



ORDER N.~ HAPLOMI. 



(The Haplomom Fishes.) 



~No precoracoid arch. Parietal bones separated by the snpraoccipital. 

 A symplectic. Opercular bones present. Anterior vertebra 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 placed 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. (6.-Xo6q, 

 simple; ty/j>?, shoulder; in allusion to the want of the precoracoid arch.) 



(Physostomi part (families Esocidte, Umbridce, Cypr'modontidce and Heteropygii) Giin- 

 tlier, vi, vii.) 



ANALYSIS OF FAMILIES OF HAPLOMI. 



o. Margin of upper jaw formed by premaxillaries alone; ovoviviparons. 



b. Vent jugular; premaxillaries scarcely protractile AMBLYOPSID^S, 48. 



lib. Vent abdominal ; premaxillaries freely protractile CYPRINODOXTIDYE, 49. 



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

 tractile. 



c. Jaws not produced ; teeth villiforrn, equal UMBRiDjE, 50. 



cc. Jaws produced ; teeth cardiform, unequal .* EsocnxE, 51. 



FAMILY XLVIIL AMBLYOPSID^E. 



(TJie 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 6. Gill- rakers very short. Pseudobranchise 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| 

 in length ; anal higher, longest ray 6 in length ; pectoral equals height of dorsal ; 

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

 Kansas. (Gill.) 



