SYSTEMATIC CATALOGUE OF FISHES. 49 



Sub-class TELEOSTOMI. The True Fishes. 



The true fishes herein considered fall into 2 groups or series, the ganoids 

 (p. 54) and the bony fishes, or teleosts (p. 61), the leading features of which are 

 noted under the respective captions. The numerous families represented in the 

 local fauna and differentiated in the following key may be divided into 4 groups 

 based on the character of the ventral and dorsal fins, as follows: I. Ventral 

 fins attached to abdomen, 1 dorsal fin; II. Ventral fins attached to abdo- 

 men far posterior to pectoral fins, 2 dorsal fins, the anterior composed of 

 spiny rays; III. Ventral fins attached to thorax or throat, under, anterior to, 

 or slightly behind pectorals; IV. Ventral fins absent. 



/. Ventral fins attached to abdomen; 1 dorsal fin. 

 a. An adipose fin behind the dorsal fin. 



b. Barbels (4 to 8 in number) on upper and lower jaws; a stout spine in dorsal and pectoral 



fins; body not scaled Silurid^ (cat-fishes). 



bb. Barbels wanting; no spine in dorsal or pectoral fins; body scaled. 



c. Margin of upper jaw formed by maxillary bone, which has asupplemental bone; air- 

 bladder large; pyloric coeca numerous; species chiefly fresh water. 



SalmonidjE (trouts and salmons). 

 cc. Margin of upper jaw formed by a long and slender premaxillary; air-bladder small 



or absent; pyloric coeca few; species marine Synodontid^ (lizard-fishes). 



aa. No adipose fin behind the dorsal fin. 

 d. Tail heterocercal. (Ganoid fishes.) 



e. Body without true scales; mouth inferior. 



/. Skin naked; barbels absent; snout paddle-shaped. 



PoLYODONTiD^ (paddlc-fishes). 

 //. Skin with 5 rows of bony shields; 4 barbels present; snout elongate. 



AciPENSERiD^ (sturgeons). 

 ee. Body scaled; mouth terminal. 



g. Scales cycloid; snout short; dorsal fin very long. 



AMiATiDiE (fresh-water dog-fishes). 

 gg. Scales ganoid; snout greatly elongated; dorsal fin very short. 



Lepisosteid^ (fresh-water gars) 



dd. Tail homocercal. (Non-ganoid fishes.) 



h. Pectoral fins inserted relatively high on sides, on or near the axis of body; lateral 

 line low, on side of belly; lower pharyngeal bones united; form very elongate. 

 i. One or both jaws produced into a long slender beak; pectoral fins small. 

 j. Both jaws greatly produced; jaw teeth both long and short. 



Tylosurid^ (marine gars). 

 jj. Only lower jaw greatly produced; jaw teeth small. 



HEMiRHAMPHiDiE (half-bcaks). 

 ii. Neither jaw produced into a long, slender beak; pectoral fims very large, used as 



organs of flight _. . ExocoETiDiB (flymg-fishes). 



hh. Pectoral fins inserted relatively low on sides, below axis of body; lower pharjmgeal 

 bones separate. 



k. Gill-membranes united to istlimus; head scaleless; jaws without teeth; dorsal fin 

 inserted near middle of back. 



I. Gill-membranes more or less completely imited to isthmus; vent close behind 

 gill-openings; small fishes, mostly without external eyes (the local representa- 

 tive of family with small eyes and no ventral fins). 



Amblyopsid^ (blind- or cave-fishes). 

 II. Gill-membranes broadly united to isthmus; vent posterior; eyes normal. 



TO, Margin of upper jaw formed by premaxillary m middle and maxillary on 

 side; pharyngeal teeth nmnerousand in a single row. 



Catostomid^ (suckers). 

 mm. Margin of upper jaw formed exclusively by premaxillaries; pharyngeal 



teeth few (less than 8) and in 1 to 3 rows Cyprinid^ (minnows). 



kk. Gill-membranes not united to isthmus. 



n. Head scaly; jaws with teeth; upper jaw protractile or not; color not silvery. 



