THE FISHES OF PORTO RICO. 
219 
Genus 99. OFHIOSCION Gill. 
This genus is composed of small species, nearly all American, allied to Scisena ( Scixna umbra L. ), 
but differing in the armature of the preopercle, its bony margin being at all ages armed with strong 
persistent serrae, the lowermost teeth not directed forward. The caudal fin in this group is never 
lunate; the soft dorsal and anal are scaly; teeth in bands; gillrakers rather short. 
There are 7 or 8 American species of this genus, all except 0. adustus being known only from our 
Pacific coast. 
175. Ophioscion adustus (Agassiz). 
Head 3.25; depth 3 3; eye 4.2; snout 3.2; maxillary 2.8; mandible 2.5; interorbital 3.7; pre- 
orbital 5.4; D. xi-r, 22; A. n, 7; pectoral 1.5; ventral 1.5; caudal 1.4; scales 6-56-10. Body compressed, 
the dorsal outline of trunk trenchant, ventral outline of body nearly straight, the dorsal outline 
evenly arched; caudal peduncle long and thin; top of head not trenchant, evenly convex; snout 
rather long and blunt, scarcely projecting beyond the small inferior mouth; several pores and clefts 
in fleshy tip of snout; chin with five pores, the middle one, at symphysis, smallest; lower jaw well 
included; maxillary reaching anterior edge of pupil or middle of eye; teeth in both jaws, in villiform 
bands, the outer row in upper jaw enlarged; top of head, cheeks, and opercles scaled; snout and 
under parts of head naked; eye moderate, nearer tip of snout than gill-opening; preopercular serrse 
rather blunt, 9 or 10 in number; dorsal fin deeply notched, the spines weak, flexible, sharp, with 
filamentous appendages projecting beyond their ends, the first very short, the third longest, the rest 
graduated to the tenth, which is shortest, the eleventh being somewhat longer, the twelfth much 
longer, pertaining to the soft portion of the fin, which is scaled on membrane between rays; ventrals 
rather long and slender, outer rays slightly filamentous, reaching about to vent; anal small but high, 
first spine very short, second very long and strong, 1.6 in head, longest ray about equaling second 
spine; caudal large, rounded, finely scaled. 
Color in spirits: Everywhere brownish with a bluish iridescence, save under parts, which are 
pale; the brown color on lower part of side is broken up into spots, which are darker at center; faint 
longitudinal brown lines following rows of scales, plainest below, scarcely evident in some specimens; 
anal and the paired fins grayish-black; dorsal and caudal like body; one specimen has scarcely any 
brown color, is grayish above and white below. 
Five specimens, 3 to 3.5 inches in length, from Vieques and Arroyo. These differ in certain respects 
from Agassiz’s colored figure of Scixna adusla — chiefly in the larger eye, in the shorter straight portion 
of lateral line, and in the length of the second anal spine, which equals the longest rays, but is only 
half as long in the drawing. Nevertheless, we believe that our specimens are the young of Agassiz’s 
species. The artist was manifestly somewhat inaccurate in his reproduction, as in the number of soft 
dorsal rays, and certainly in the omission of the short first anal spine. Moreover, the drawing was 
based upon a specimen much larger than ours (lOinches). We think these considerations are sufficient 
to explain the differences. The description of 0. adustus in Jordan & Evermann’s Fishes of North 
and Middle America hardly applies to the Scixna adusta of Agassiz, but is based upon a specimen from 
Pernambuco, which probably belongs to some other species. 
Scisena ( Corvina ) adusta Agassiz, Spix, Pise. Brasil., 126, pi. 70, 1829, Montevideo. 
Genus 100. MICR0P0G0N Cuvier & Valenciennes. Croakers. 
Body moderately elongate, compressed, somewhat elevated; preopercle strongly serrate; teeth 
in villiform bands, outer row in' upper jaw enlarged; lower jaw with a row of minute barbels on each 
side; gillrakers short, thickish; spinous dorsal rather short, of 10 or 11 stoutish spines; second anal spine 
moderate; caudal fin double-truncate; lower pharyngeals narrow, distinct, with sharp conical teeth; 
air-bladder with long horns. A well-marked genus, the species all American, allied to Ophioscion and 
Scixnops, but distinguished by the presence of barbels; species all closely related, similar in form, size, 
and color, and all of value as food-fishes. 
a. Dorsal rays x-i, 28 to 30. 
b. Scales comparatively small, about 9 in a vertical series between front of dorsal and lateral line, 12 in an oblique 
series; outer teeth of upper jaw evidently enlarged; dark spots on scales above lateral line not forming contin- 
uous stripes; scales 54. undidatus 
