GILBEET AND STARKS — FISHES OF PANAMA BAY 31 



47. Tachysurus emmelane Gilbert. 



Platk VI, Figs. 11 iiml 11a. 

 Tachysun(s cnniiclanc Gilbert, Jordan & Evermann, 1898, j). 2785. 



Head 3| in length (4^*^ in total); depth 5 (6 in total). A. 27 (3+24). Eye 7 in head, 

 2\ in its distance from tip of .snout, 4 in postorbital part of head, 35 in interorbital width, 2\ in frontal 

 width opposite middle of eyes. Mouth of modenite width, gently conve.x, the distance between its 

 angles (measured internally) 2| in head. 



Teeth in premaxillary and front of mandible finely villiform; posterior mandibular teeth 

 stronger than those in front, bluntly conic, not, however, coarsely granular, as are the posterior man- 

 dibular teeth in T. furthii, T. melanopus, and T. liropus. Mandibular bands with a wide interspace 

 niesially, each widest near symphysis, rapidly tapering laterally, and extending beyond angle of mouth. 

 The width of the bands is less than in related species, \ eye at their widest point. The length 

 of one of the mandibular bands is slightly greater (i-jV) thi'n length of eye. Premaxillary band very 

 short, its length but \ greater than that of one of the mandibular bands, extending on each side 

 less than i distance from median line to angle of mouth; width of band 5 its length. Palatine teeth 

 granular, in small oblanceolate patches, which taper to a point laterally, and are widely separated 

 on median line, the patches agreeing in size and shape with, those in T. liropus. 



Head depressed, tapering, and at the same time narrowing anteriorly, as in other species of 

 Tachysurus ; profile rising in a uniform, gently convex curve to occiput, where it becomes concave, 

 owing to the more rapidly ascending outline of the occipital process. Eye low, but little above angle 

 of mouth, the interorbital space decidedly convex. Barbels slender, the maxillary barbels reaching 

 edge of gill-membrane in front of pectoral spine, the outer mental barbels extending beyond gill- 

 membrane, i| in head; the inner not to edge of membrane. Gill-membrane widely attached to 

 isthmus, without free edge. 



Occipital region with very fine granulations, those on middle of occiput forming parallel series 

 along the fontanel groove, those on median portion of occipital process in series which diverge back- 

 ward from the median line. The sculptured area extends forward to a vertical which traverses the 

 cheek at a distance of its own diameter behind the eye; anterior edge of granulated area equidistant 

 between the tip of snout and front of predorsal plate. Fontanel produced backward as a deep, narrow 

 groove, which fails to reach base of occipital process by a distance equaling half the length of the 

 process on the median line. The groove widens but little anteriorly; an area behind and on each side 

 of the groove with parallel series of granulations, and marked off from the rest of the head by a 

 shallow trench. Base of occipital process similarly indicated by a transverse indented line; occipital 

 process not keeled, very wide at base, becoming abruptly very narrow behind, its posterior third 

 having parallel margins and being as wide as long, the lateral margins therefore deeply concave; width 

 of process at base equaling its length on median line plus that of predorsal plate, its hinder edge deeply 

 incised to receive the anterior rounded wedge-shaped process of the predorsal plate. The latter is finely 

 granulated anteriorly, the lateral wings concealed under the smooth skin. A narrow groove as long as 

 eye occupies the anterior end of the fontanel. Opercle without radiating ridges. A short, slit-like 

 axillary pore present. Humeral process short, the exposed portion not broadly triangular, the surface 

 smooth, or indistinctly rough. Gill-rakers 6-j-i3, of moderate length and thickness, the longest below 

 the angle, f diameter of eye. 



Dorsal spine with a series of obtuse granulations in front and very weak retrorse serree behind, 

 its length to tip of calcified portion i| in head; longest soft ray if in head. Adipose dorsal not 

 adnate, its anterior insertion about over middle of anal; base of adipose dorsal much greater than 

 its height, less than base of first dorsal; distance between dorsals equal to length of head. Pectoral 

 spine strong, ridged and granulated in front, the hinder edge with very strong seme; length of 



