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86. R. lunatus, Cope. Fork-tailed Dace. Specimens from Rock river 
are in Prof. Jordan’s collection. 
87. R. meleagris, Ag. A very large number of specimens of this 
species are in the state collection, from Bailey’s creek, McLean county, 
where Prof. Forbes found them in abundance. Agassiz’s description is so 
incomplete that I insert the following from one of the Illinois specimens. 
The species is well marked, and may be easily recognized. A few specimens 
were taken in the V ermilion river : 
Head 2 2-5 in length ; depth 4*. Eye small, 5 in head. D. I, 7 ; A. 
I, 6. The barbels are long and distinct. The snout projects considerably, 
overlapping the lower jaw. Dorsal much nearer tail than tip of snout. 
Upper half of body dark, sharply outlined by the light of the under parts. 
The dark mottlings are not so profuse as in most of the species. The body 
is stout, deeper and thicker than in most members of the genus. 
Genus Pfienacobius , Cope. 
88. P. teretulus , Cope , var. liosternus , Nelson. A number of specimens 
of this form are in the state collection, from small streams in McLean county, 
where it appears not to be uncommon. The following is the description of 
the adult : 
Head 4£ in length: depth 4f. Eye 4£ in head. D. I, 7 ; A. I, 7 ; 
ventrals 8. Lateral line 43 to 45 ; longitudinal rows 5-4 ; scales in front 
of dorsal, 16 ; length 3 inches. Dorsal in front of ventrals, much nearer 
snout than caudal. Scales in front of dorsal small. Intestine short, peri- 
toneum pale. Head long; mouth inferior, lateral line first decurved, then 
straight. Pectorals do not extend to ventrals, ventrals reach vent. Teeth 
4-4, hooked. Color olive above, sides bright silvery overlying a plumbeous 
shade ; a small but distinct caudal spot. Thoracic region entirely naked. 
Lips fleshy, as in the Catostomidae. 
Genus Hybopsis , Ag. 
89. H. storerianus , ( Kirt .) Ag. Storer’s Minnow. Two specimens in 
my collection, from Lake Michigan at Chicago. The following is the de- 
scription of one of the specimens : 
Head in length 4f ; depth 4f ; eye in head 3 times, and longer than 
snout ; very large and white. D. I, 8 ; A. I, 7. Lat. 1. 40. Dorsal over 
ventrals, nearer snout than to caudal ; 20 large scales in front of dorsal : 
lateral line nearly straight ; pale above, sides bright silvery : intestine 
short ; peritoneum white. This species presents much the appearance^of 
amarus , Grd. 
90. H. hudsonius, (Clint.') Put. Spawn-eater. Occurs in Lake Michi- 
gan. (Jordan.) 
91. H. tuditanus, Cope. Described from Lake Michigan. I have seen 
no specimens. 
92. H. stramineus , Cope. Very common in creeks through centra) 
Illinois, and probably occurs elsewhere, but no specimens have been taken. 
93. H. volucellus , Cope. Specimens have been received from the 
Rock and Pecatonica rivers, by Prof. H. E. Copeland. 
