BULLETIN OF THE UNITED STATES FISH COMMISSION. 49 



Head 3| (4|) ; width of head 5 (('>'), depth G£ (7). Length (28140) 12£ 

 inches. D. I, G ; P. I, 10; A. 3, 15. 



Body slender, its width anteriorly greater than its depth ; caudal pe- 

 dnncle compressed, short; distanee from end of anal to base of median 

 caudal rays about one-half length of head. Head depressed, not very 

 broad; its depth at posterior margin of branehiostegal membranes less 

 than three-fifths its width ; interorbital region flat, smooth, the smooth 

 area forming a broad equilateral triangle, its base at the interorbital 

 space, the apex at a point four-ninths the distance from snout to dorsal, 

 the triangle forming the termination of the almost obsolete fontanelle; 

 ' top of head, occipital process, and ante-dorsal shield finely granular, 

 some of the anterior granulations only arranged in lines, none of them 

 in radiating stride. Occipital process broadly trapezoidal, its width 

 slightly greater than the length of its side, with a slight or obsolete 

 median carina ; its posterior margin truncated ; its sides slightly convex 

 posteriorly, concave toward the front; ante-dorsal shield small, narrow, 

 crescent-shaped, its median length about half the length of its side. 

 Eye small, G in head; interorbital width 2f- in head; snout 4 in head; 

 breadth of mouth 2. Maxillary barbel very slender, reaching base of 

 pectoral spine; outer mental barbel to well beyond margin of branehi- 

 ostegal membranes, its length about half head ; inner mental barbel 3 

 in head. 



Teeth all villiform ; width of premaxillary band about one-sixth its 

 length. Vomerine and palatine bands of teeth, fully confluent on each 

 side, forming together a crescent-shaped patch, narrowly divided on the 

 median line of the vomer; form of vomerine band similar to that of the 

 palatine band. Palatine band of teeth without backward prolongation. 

 Opercle with radiating ridges ; humeral process granular, narrow, pro- 

 duced backward, not quite half-length of pectoral spines; no axillary 

 pore. Gill-membranes forming a narrow fold across isthmus. 



Dorsal short, its base about equal to that of adipose dorsal ; dorsal 

 spine robust, but little shorter than pectoral spine, about three-fifths 

 length of head ; its anterior seme small and tubercle-like; its posterior 

 edge, as well as that of pectoral, retrorsely serrate; soft rays of dorsal 

 rays extending much beyond the spine, the longest about three-fomihs 

 length of head. Adipose dorsal about one-half as high as long, its pos- 

 terior margin largely free. Caudal very widely forked, the upper lobe 

 falcate, nearly one-third longer than the lower, as long as head. Anal 

 short and low. Distance from vent to base of ventral s slightly more 

 than one-half its distance from origin of anal. Pectoral spine very 

 strong, much stronger than dorsal spine, its anterior margin with sen ;e 

 towards the tip, becoming small tubercles towards base; inner edge 

 with strong retrorse serrre, the soft rays longer than spines, reaching 

 three-fourths distance to base of ventrals. 



Color very dark bluish or greenish above ; sides with bronze lustre : 

 belly silvery. Mental barbels white, with black edge; maxillary bar 

 Bull. U. S. F. C, 82 4 Oct. 6, 1 8 82. 



