HIODONTUXiE. — XXVII. 6 9 



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

 everywhere abundant in sluggish or weedy waters. 



S. E. (X. 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. (C>iprinus americanus L., 1766, not of 1758) (xpvaos, gold; 

 XeuKoy, white.) 



Order XIII. ISOSPOXDYLI. (The Salmon, Herring, 



ETC.) 



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

 agree in lacking the modified vertebra 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, {laot, equal ; 

 (rnovbvXos, vertebra). 



Family XXVII. HIODONTID^h (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 

 fine 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. (ioeiSfc, hyoid (bone) ; 68^, tooth.) 



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

 developed rays 



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

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

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

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

 lustre. Head 41; depth 31. D. 9. A. 32. Scales 6-56-9. L. 1 _>. 

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

 fiSos, 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 



