HIODONTIM. XXVII. 69 



(12 to 14). Scales 10-51-3. L. 12. Maine to Dakota and La., 

 everywhere abundant in sluggish or weedy waters. 



S. E. (N. C. to Ala.) occurs var. bosci (Cuv. & Val.) with A. 

 longer, about 16 ; the scales larger, 8-43-2, and the lower fins scar- 

 let in males. The two forms intergrade and both are very varia- 

 ble. (Cyprinus americanus L., 1766, not of 1758) (xpueros, gold; 

 \evKos, white.) 



ORDER XIII. ISOSPONDYLJ. (THE SALMON, HERRING, 



ETC.) 



This order contains a great variety of soft-rayed fishes, which 

 agree in lacking the modified vertebras and the falciform pharyn- 

 geals of the preceding order, and in having a more complex struc- 

 ture of the shoulder-girdle than the Haplomi. There are 20 or 25 

 families, most of them marine ; some in the deep seas. (iVos-, equal ; 

 vertebra). 



FAMILY XXVII. HIODONTID^E. (THE MOON-EYES.) 



Body oblong, much compressed, covered with large, silvery cy- 

 cloid scales ; head naked ; mouth terminal, oblique ; margin of 

 upper jaw formed by intermaxillaries mesially and by maxillaries 

 laterally ; maxillaries entire ; no barbels ; no adipose fin ; lateral 

 line distinct ; abdomen compressed, not serrated ; moderate sized 

 teeth on jaws, vomer, sphenoid, hyoid, pterygoid, and palatine 

 bones ; tongue with sharp canines ; gill rakers few, short, thick ; 

 eye very large ; gill openings wide ; one pyloric appendage ; air- 

 bladder simple ; no oviducts. One genus, with three species, inhab- 

 iting our Western Streams and the Great Lakes, handsome fishes, 

 of little value as food. 



67. HIODON Le Sueur. (voei&fc, hyoid (bone) ; o&oi/, tooth.) 



a. Belly strongly carinate, both before and behind V. ; D. very small, of nine 



developed rays. 



160. H. alosoides (Rafinesque). Body deep, closely com- 

 pressed ; snout blunter than in other species ; eye moderate, 3^ in 

 head ; P. short, nearly as long as head, about reaching V. ; longest 

 dorsal ray about half longer than base of fin ; sides with golden 

 lustre. Head 4 ; depth 31. D. 9. A. 32. Scales 6-56-9. L. 12. 

 Ohio Valley to Saskatchewan R., common N. (Lat., alosa, shad ; 

 , form.) 



aa. Belly scarcely carinate before V.; dorsal rays (developed) 12. 

 b. Belly carinate between V. and A. 



161. H. tergisus Le Sueur. MOON-EYE. SILVER BASS. 

 TOOTHED HERRING. Snout rounded, shorter than the large eye, 

 which is 3^ in head. Olivaceous, sides brilliantly silvery. Head 



