874 FISHES — HTODONTID^. 



Diagnosis. — From all other Ohio fishes, this species may be known by 

 the serrated belly, in connection with the projecting lower jaw. 



Habits. — In regard to distribution, habits and value as food this 

 species is essentially like the Gizzard Shad. It is found only in the 

 larger rivers and ponds, never ascending the small streams. Compara- 

 tively lately, it has made its way into the Lakes. It is migratory to some 

 extent, but whether individuals ever descend from Ohio to the Gulf of 

 Mexico, is not yet known. It is a handsome fish, but it does not reach a 

 very large size, and its flesh being dry and bony, it is not valued as food. 

 The name Skipjack alludes to its habit of leaping from the water. It 

 feeds upon small fishes, insects and probably crustaceans. 



FAMILY XII. HYODONTIDiE. THE MOON EYES. 



Clnpeoid fishes with the mouth moderate, obliqae, terminal, the ja.w8 abont eqnal, 

 the maxillary reachiDg to aboat opposite the middle of the eye ; maxiUary small, slender, 

 withoat supplemental bones, articulated to the end of the premaxillary, and foiming 

 the lateral margin of the upper jaw ; eye exceedingly large, much longer than the thick, 

 bluntish snout ; dentition greatly developed, nearly every bone in the mouth being 

 provided with bands of teeth ; premaxillary and mandible provided with rather stout vill- 

 iform teeth; maxillariea with feeble teeth; tongue with two marginal rows of very long 

 canines, between which is a band of close set, shorter, almost paved teeth ; vomer with 

 a similar long series of paved teeth, but without canines; palatines with long series of 

 close set teeth, a similar series on the pterygoids and on th^ sphenoid bone ; sides of 

 lower jaw shutting within the upper, so that the dentaries fit against the palatines ; 

 gill membranes entirely separate, the branchiostegals eight to ten in number ; scales 

 large, brilliantly silvery, cycloid; lateral line distinct, straight; body oblong, 

 compressed, rather deep, belly with ordinary scales, rounded or ciriuated ; dorsal fin 

 well back, beginning opposite the vent ; veutrals well developed ; caudal fin strongly 

 forked A single genus, with abont three species, inhabiting the fresh waters of North 

 America, remarkable for their brilliantly silvery coloration. 



Genus 48. HTODON. LeSueur. 



Biodon, LbSueur, Jonru. Acad. Nat. Sci. Phila., i, 1818, 364. 



Ghssodon, Bafinesque, Amer. Monthly Mag., ii, 1818, 354. 



Amphiodoti, Rafinesque, Journal da Physique, 1819, 4J21 (alosoidea). 



CUtdalus, Rafinesqub, Ich. Oh., 1820, 43. 



Gloasodon, Heckbl, Russegger's Reisen, i, 1843, 1033. 



UlattonitHus, Gill and Jordan, Ball. U. S. Nat. Mas., x, 1877. (Subgenus.) 



Type, Hiodon tergisua, LeSueur. 



Etymology, huoeidea, hyoid bone, i.e., bone shaped like the letter upsilon ; odon, tooth 

 (in allusion to the toothed tongue). 



Generic characters not separable from those of the family. 



