GILBEKT AND STAUKS — FISUES OF PANAMA HAY 31 



47. Tachysurus emmelane Gilbert. 



Platk VI, Fitis. II iiiul ll'i. 

 Tachysurus cnimclane Gilbert, Jordan & Evkrmann, 189S, p. 2785. 



Head 3j in length (4,'j 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 jjart of head, 3I in interorbital width, 2 J in frontal 

 width opposite middle of eyes. ^foiilh of moderate width, gently convex, the distance between its 

 angles (measured internally) 2 J 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.Jurtltii, T. iin/aiiopus, and 7". 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 si^ecies, \ eye at their widest jxjint. The length 

 of one of the niandil)ular bands is slightly greater (i|V) l'^''" length of eye. Prema.xillary band very 

 short, its length but \ greater tlian tlial of one of the manilibular bands, e.xtending on each side 

 less than 1 distance from median line to angle of moutii; width of band 5 its length. Palatine teeth 

 granular, in small oblanceolate i)atclies, which taper to a jjoint 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 occii)ut, 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 liarbels reaching 

 edge of gill -nienibrane in front of pectoral spine, the outer mental barbels extending Ixryond gill- 

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

 istliiiius, 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 sculirtured 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 antl front of predorsal plate. Fontanel produced backward as a deep, narrow 

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

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

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

 shallow trench. Base of occij)ital 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 predors;il jjlate, its hinder edge deeply 

 incised to receive the anterior rounded wedge-shaped process of the pretlorsal 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 

 a.\illary pore present. Humeral process short, the exposed portion not broadly triangular, the surface 

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

 the angle, § diameter of eye. 



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

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

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

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

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



