22 ZOOLOGY. 



5. ACOMUS GRISEUS, Grd. 

 Gen. Rep. 222.— Plate XLIX, Figs. 5—9. 



Spec Char. — Head constituting the fifth of the entire length. Mouth moderate sized. Granules of lower lip largest close 

 to the mouth. Eye email, sub-elliptical ; its longitudinal diameter entering about seven times in the length of the side of the 

 head. Anterior margin of dorsal fin equidistant between the extremity of the snout and the insertion of the caudal. 

 E.xtreniities of ventrals not reaching the vent ; their origin taking place under the posterior third of the dorsal. Greyish browa 

 above ; whitish or yellowish beneath. 



259. Sweet water, tributary of Platte river, Nebraska. J. S. Bowman. 



6. PIMEPPIALES MACULOSUS, Grd. 



Gen. Rep. 234. 



Spec. Char. — Body rather short, deep, and compressed; greatest depth equal to one-fourth of the total length, whilst the 

 head constitutes the fifth part of it. Eye moderate and circular ; its diameter entering four times in the length of the side 

 of the head. Anglo of the mouth not extending as far as a vertical line drawn in advance of the orbit. Extremities of 

 ventrals overlapping the vent, and reaching the anterior margin of the anal. Scales much deeper than long, and larger on the 

 peduncle of the tail than anteriorly. Yellowish brown with black blotches. 



153. Sluice of Arkansas river. Mr. Kreuzfeld. 



7. HYBOGNATHUSPLACITUS, Grd. 



Gen. Rep. 236. 



Spec. Char. —Body sub-fusiform in profile. Head sub-conical, contained about five times and a half in the total length. 

 Eye moderate sized, sub-circular. Anterior margin of dorsal Cn nearer the extremity of the snout than the base of the 

 caudal, whilst the insertion of the ventrals is nearly equidistant between the same points. Scales anteriorly rounded. Greyish 

 brown above, silvery on the flanks, and dull metallic white beneath. 



89. Sluice of Arkansas river near Fort Makee. Mr. Kreuzfeld. 



8. HYBOGNATHUS EVANSI, Grd. 

 Gen. Rep. 236. 



Spec. Char. — Body sub-fusiform in profile. Head sub-conical, thickish, contained about five times in the total length. Eye 

 moderate sized, sub-circular. Anterior margin of dorsal fin equidistant between the extremity of the snout and the base of 

 the caudal. Insertion of ventrals being situated posteriorly to the anterior margin of the dorsal, is therefore nearer the base 

 of the caudal than the extremity of the snout. Caudal fin constituting the fifth of the total length. Scales anteriorly truncated. 

 Keddish brown above ; silvery on the flanks and beneath. 



90. Sweetwater, tributary of Platte river. J. S. Bowman. 



9. ALGANSEA OBESA, Grd. 

 Gen. Rep. 239. 



Sped. Char. — Head contained four times and a half in the total length. Eye rather small ; its diameter entering nearly six 

 times in the length of the side of the head. Posterior extremity of the maxillar bone corresponding to a vertical line drawn 

 behind the nostrils. Anterior margin of the dorsal fin nearer the insertion of the caudal than the extremity of the snout. 

 Insertion of ventrals nearer the base of the caudal than the t^xtremity of the snout. Scales moderate. Bluish grey above ; 

 yellowish beneath ; sides greyish. Fins greyish olive. 



193. Humboldt river. J. S. Bowman.— 194. ?. Mr. Kreuzfeld. 



