768 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxx. 



traverses the granulated area on top of head, where for a distance 

 e(iual to the long diameter of the e3^e it is sharply defined, and as wide 

 and deep as the base of the slender maxillary barbel. Posteriorly it 

 ends in a point; anteriorly it is continued as a faint line with indefinite 

 gently rounded edges to in front of the ej'es, where it abrupth^ 

 becomes wider, deeper, and sharply defined for a short distance and 

 ends opposite the posterior nostril. Occipital process as wide as its 

 length with the addition of the median length of the ver}^ narrow 

 dorsal plate. The keel of the occipital process is sharp and high, with 

 a slightly concave area on each side of it; at a little behind the middle 

 of its length its sides slope away from the median keel at an angle of 

 45'-'. Snout as viewed from abo^•c rather narrow and evenly rounded. 

 Premaxillary ))and of teeth as long as eye and one-fifth as wide; 

 palatine patches small, elliptical, and widely separated, each bearing 

 about 30 bluntly rounded teeth; length of each patch two-fifths of 

 length of eye and half as wide as long. Posterior, median, mandibular 

 teeth not enlarged as in other species. Eye large; scarcel}^ above level 

 of mouth; the beginning of its posterior fifth at middle of length of 

 head. Maxillary barbel reaching to axillary pore; postmental barbel 

 to base of pectoral spine; and mental barbel to base of l)ranchiostegal 

 membrane. Branchiostegal membrane forming a fold across isthnuis. 

 Gill rakers rather long and slender; those near angle of arch half as 

 long as eye; 6 + 13 in number. 



Pectoral reaching to opposite base of last dorsal ra^^; the ventrals 

 not quite to front of anal. Anal high anteriorly; its posterior edge 

 very slightly concave; its last ray coterminous with tip of adipose 

 dorsal. Posterior end of ])ase of adipose dorsal two-thirds of head^s 

 length from base of caudal rays. 



Color ver}^ dark l)rown above, changing gradually on sides to dirty 

 white on lower parts; head dark to below e^'e; barbels all black; 

 dorsal and adipose dors>il dusk}^; anterior half of anal growing lighter 

 behind; upper surface of ventral and pectoral blue black; the former 

 growing-lighter toward ends of rays; their lower surface dusky; caudal 

 dusky. 



This species appears to be related to T. steindachnerl., but not 

 closely. The eye is much larger, the occipital process much sharper, 

 the fontanel not so large; the profile straighter and steeper; the head 

 sharper; and the character of the mandibular teeth different. 



The type and sole specimen of this species was collected at Guaya- 

 quil, Ecuador. It is 193 mm. in length and is deposited in the U. S. 

 National Museum, Cat. No. 53-170. 



