HIODONTIDA, — XXVIL 69 
(12 to 14). Scales 10-51-3. IL. 12, Maine to Dakota and La. 
everywhere abundant in sluggish or weedy waters. 
S. E. (N. C. to Ala.) occurs var. bosei (Cuv. & Val.) with A. 
longer, about 16 ; the scales larger, 843-2, 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) (xpucés, gold ; 
Aevuxos, white.) 
OrpvEeR XIII. ISOSPONDYLI. (Tue Saumon, Herrine, 
ETC.) 
This order contains a great variety of soft-rayed fishes, which 
agree in lacking the modified vertebre 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. (ios, equal ; 
omovdudos, vertebra). 
Famity XXVIII HIODONTIDAH. (Tue Moon-eyves.) 
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. (toevd4s, hyoid (bone); é8év, 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, 34 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 44; depth 34. D.9. A. 32. Scales 6-56-9, L. 12. 
Ohio Valley to Saskatchewan R., common N. (Lat., alosa, shad; 
etdos, form.) 
aa. Belly scarcely carinate before V.; dorsal rays (developed) 12. 
b. Belly carinate between V. and A. 
161. H. tergisus Le Sueur. Moon-rre. Sitver Bass. 
TootuEp Herrine. Snout rounded, shorter than the large eye, 
which is 34 in head. Olivaceous, sides brilliantly silvery. Head 
