NATURAL SCIENCES OF PHILADELPHIA. 201 



teriorly to the base of the pectorals and the anterior margin of the dorsal ; their 

 tips overlapping the vent. Scales rather large. Pale reddish brown, lighter 

 beneath than above. Fins greyish olive ; dorsal with a black patch. 

 Collected in the Rio Blanco, Texas. 



8. Bryttds signifer. — Body contracted and deep. Nape convex and snout 

 subconical. Posterior extremity of maxillary extending to a vertical line drawn 

 in advance of the pupil. Insertion of ventrals situated posteriorly to the base 

 of the pectorals and the origin of the dorsal ; their tips overlaj»ping the vent. 

 Scales moderate. Keddish brown, lighter beneath than above. Dorsal and 

 anal fins provided with a black patch. 



Caught in the Rio Medina, Texas. 



9. Bryttus humilis. — Body subelliptical. Nape convex and snout subconical. 

 Posterior extremity of maxillary extending beyond the anterior rim of the orbit. 

 Insertion of ventrals situated posteriorly to the base of the pectorals and a little 

 in advance of the origin of the dorsal ; their tips overlapping the vent. Scales 

 large. Reddish brown or dusky, maculated. Fins unicolor ; dorsal sometimes 

 blotched. 



Inhabits the fresh w .ters of Arkansas. 



10. PoMoTis LUNA. — Body subcircular when viewed in profile. Head moder- 

 ate ; snout subconical. Mouth small; posterior extremity of maxillary extend- 

 ing to a vertical line drawn in advance of the anterior rim of the orbit. Eye 

 moderate. Suborbital and suprascapular bones not crenated. Edge of pre- 

 opercle very slightly crenated. Opercular flap small. Spinous portion of dorsal 

 fin of moderate height and lower than the soft ; its origin being situated op- 

 posite the base of the pectorals and consequently in advance of the origin of 

 the ventrals. Caudal fin posteriorly emarginated. Tips of ventrals overlapping 

 the vent, but do not reach the anterior margin of the anal fin. Extremities of 

 pectorals nearly even with the tips of ventrals. Greenish-brown above, yellow- 

 ish beneath ; sides of head with blue and yellow lines. Fins unicolor, vertical 

 ones greyish olive, the others yellowish. 



Collected at Fort Snelling, Minnesota. 



11. LuctoPERCA BOREA. — Body slender, elongated and subfusiform. Snout 

 conical. Mouth deeply cleft; posterior extremity of maxillary extending to a 

 vertical line drawn posteriorly to the orbit. Scales on the cheek and opercle 

 not deciduous, larger upon the opercle than upon the cheek. Insertion of ven- 

 trals situated posteriori to the base of pectorals, and a little anteriorly to the 

 origin of the first dorsal. Posterior margin of caudal fin crescent-shaped. 

 Anus placed opposite the anterior margin of the second dorsal fin. Yellowish or 

 olivaceous, spotted with black. 



From Fort Sarpi, Nebraska. 



CHIROPSIS. — Body subfusiform, head well developed. Mouth of medium 

 size ; slender canine teeth on both jaws ; velvet-like teeth on the front of the 

 vomer and along the palatines. Opercle and preopercle without either spines or 

 serratures. Cheeks, opercular apparatus, and upper surface of head covered 

 with small scales. A supraoculary, arborescent, membranous flap. Gill open- 

 ing continuous under the throat. Branchiostegal rays six in number. Two 

 dorsal fins, a spinous and an articulated one, occupying most of the dorsal 

 region. Insertion of ventrals situated behind the base of the pectorals. Caudal 

 fin posteriorly rounded or subtruncated. Scales finely pectinated posteriorlv. 

 Several lateral lines. 



This genus is to include the species which we have formerly described under 

 the names of Chiruspictus, C. gultatus, and C. constellatus. 



12. Oligocottcs ANALis. — Head subconical. Mouth moderately cleft ; poste- 

 rior extremity of maxillary extending to a vertical line drawn across the pos- 

 terior rim of the pupil. Preopercular spine moderate. Two acute nasal spines. 



1857.] 



