812 FISHES—CY PRINID.A. 
shovel-like mandible would appear to be adapted for removing these 
creatures from their hold on the rocks and bottom, while the great 
strength of the pharyngeal walls and muscles enables the fish to crush 
the shells before mastication with the pharyngeal teeth.” It takes the 
hook readily, and is therefore a ‘“‘ boy’s fish.” 
GENUS 31. HUDSONIUS. Girard. 
Hudsonius, GIRARD, Proc. Acad. Nat. Sci. Phila., 1856, 210. 
Hybopsis, Copr, Trans. Am. Philos. Soc., 1866, 385 (not of Agassiz). 
Photogenis, Copx, Trans. Am. Philos. Soc., 1866, 379 (in part). 
Type, Clupea hudsonia, DeWitt Clinton. 
Etymolegy, Hudson River. 
Body oblong or elongate; mouth rather small, horizontal or somewhat oblique; jaws 
normal; no barbels; teeth 4-4 or 1, 4-4, 1 (in one species 1, 4-4, 2), hooked, with grind- 
ing surface; scales large; lateral line complete; dorsal fin inserted nearly over ven- 
trals; anal fin short. A very large genus including our smallest and feeblest minnows, 
together with some of our largest species. 
This genus, as now understood, comprises three well marked subgenera, which have 
under one name or another been sometimes taken as genera. These are: 
1. Hudsonius proper, including silvery species of large size, with short heads; dorsal 
fin inserted in front of the ventrals; teeth two-rowed; scales not closely imbrica’ed ; 
fins plain. These species bear a close resemblance to Hybognathus. | 
2. Miniellus (Jordan), including small, plain species, with rather large head; dorsal 
fin inserted over ventrals; teeth one-rowed; scales large, not closely imbricated; fins 
plain. These are the smallest and most insignificant of American Cyprinide, and may 
be usually known from the young of larger species by the large scales before the dorsal. 
3. Photogenis (Cope), including species of moderate size; compressed ; dorsal fin in- 
serted behind the base of the ventrals; teeth two-rowed ; scales deeper than long, 
closely imbricated ; dorsal fin with a dark blotch on its upper posterievr portion; males 
in spring with the snout, etc., tuberculate, and the fins charged with satin-white pig- 
ment. The members of this group closely resemble certains forms referred to Cliola, and 
in some degree certain species of Luxilus. Besides the following, several other southern 
and western species perhaps occur within our limits. 
ANALYSIS OF SPECIES OF HUDSONIUS. 
* No black blotch on posterior rays of dorsal; dorsal not inserted behind ventrals ; scales 
not closely imbricated. 
t Head short, aboat 4 in length. ; 6 
; : STORERIANUS. 
tt Head comparatively long; 3% to 4 in length. 
a. Mouth inferior, horizontal. 
b. Lateral line 34; pectorals reaching ventrals. : : : VOLUCELLUS. 
bb. Lateral line 36; head stoutish; pectorals short. 6 6 STRAMINEUS, 
aa. Mouth terminal, oblique. 
ce. Lateral line 35. : ° : : FRETENSIS. 
cc. Lateral line 44. : : Q : 6 ; HZMATURUS. 
** A black blotch on posterior rays of dorsal; dorsal inserted behind ventrals; scales 
deeper than long, closely imbricated. . 4 ° .  ANALOSTANUS, 
