15G CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY IV. 
1§2. If. HMchaBis Ag . — Silvery Minnow. 
Body elongate, comparatively slender. Head moderate, rather short, 
the profile evenly curved. Eye large, rather longer than muzzle, about 
4 ill head. Upper jaw heavy; lower jaw thin. Scales large and silvery. 
Lateral line deciirved, 12-14 large scales in front of dorsal. Olivaceous 
green above, trauslnceut in life ; sides clear silvery, with bright reflec- 
tions. Eius unspotted. Head 4; depth 4 J. D. 8; A. 7; teeth 4-4; 
scales 5-38-4. L. 5-7 inches. A graceful minnow, abundant in most 
streams from New Jersey to the Upiier Missouri and southward. As 
here defined, more than one species may be included ; but, if so, the 
authors are unable to distiuguish them.) 
(Agassiz, Amer. Jouru. 8ci. Arts, 1855,224; Giinther, vii, 184; Jlyhoc/naihiis arriyritis, 
evan^i, and / vy/u/s Grd. Proc. Acad. Nat. Sci. Pliila. 1856, 182,209: Hijboyiiathus rcgins 
Giinther, vii, 185: Ht/bognathiis ounierinns Cope, Proc. Auier. Phil. 8oc. Phila. 1870, 
466: Jlybognatluis arf/yritis Jordan, 289.) 
1§3. II. amariis (Grd.) Jordan. 
Head very short, small and blunt ; front convex rather than de- 
clivous, as in n. nuchaUs. Suborbital bones rather narrow, about as in 
JI. niichalis. Scales moderate, 16 in front of the dorsal. Coloration of 
II. nuchalis, but size much smaller. D. 8 ; A. 7 ; Lat. 1. 35-38 ; teeth 
4-4. Eio Grande region. 
(Jlgoma amara Grd. Proc. Acad. Nat. Sci. Phila. 1856, 180.) 
1§4. II. flavipiiinis Cope. 
“ This fish diflers from H. argyritis {nuchalis of the iireseut memoir) in 
the smaller scales and quite different coloration. Eye large, horizon- 
tally oval, its length 2§ in head, and equal to iuterorbital width. The 
muzzle is shortly decurved to the mouth, which is terminal and short. 
The extremity of the maxillary extends half way from the end of the 
muzzle to the line of the orbit. Origin of ventral fins below or a little 
in advance of the base of tlie first dorsal ray. The pectoral is short, 
not nearly reaching the ventral, which in turn falls far short of the 
vent. The lateral line rises anteriorly. The occipital region is convex 
and rather wide, the iuterorbital region nearly flat. Color dusky above, 
a wide dusky lateral band, separated by a pale baud from the back. A 
faint dark spot at base of caudal. Fins pale yellow, unspotted. Head 
5 y in lengtli, with caudal fin; depth a little more. H. 8; A. 7 or 8; 
scales 7-41-4. L. 2^ inches. Llano Eiver, Texas.” {Cojje, MSS.) 
1§5. II. Cope. 
Similar to H. Jkivijnmm, but with larger scales. Ventral fin origi- 
nating a little in advance of the first dorsal ray. Eye large, a little 
