SOUTH AMERICAN NEMATOGNATHI. 61 



34, Tachisurus dowii, 



Leptarias dowii Gill, Proc. Acad. Nat. Sci. Philad. 1863, 170 (Pan- 

 ama). 



Arius dovii Giinther, Fish. Cent. Am. vi, 1866, 393 and 476 (copied). 



Arius dowii Jordan & Gilbert, Bull. U. S. Fish Comm. 1882, 50 

 (Panama). 



Oaleichthys dowii Jordan, Proc. U. S. Nat. Mus. 1885, 360 (name 

 only). 



Tachisurus dowii Eigenm. & Eigenm. Proc. Cal. Acad. 2d Ser. vol. 

 i, 1888, 142 (Panama). 



Arius alatus Steindachner, SB. Ak. Wien, Ixxiv, 1876, Ichthyol. 

 Beitr. iv, 19, pi. vi (Panama); id. Fisch-Fauna des Cauca und 

 der Fliisse bei Guayaquil, 45, pi. v, figs. 2-2a, 1880 (Guayaquil); 

 Jordan & Gilbert, Bull. U. S. Fish Comm. 1882, pp. 37, 39 (copied) ; 

 Jordan & Gilbert, Proc. U. S. Nat. Mus. 1882, 621 (Panama). 



Habitat: West Coast tropical America. 



Width below the dorsal spine a little greater than the 

 depth, less than the width at the humeral process which 

 equals the greatest width of the head measured at the 

 opercles. Head depressed, its depth at base of occipital 

 process 1J in the greatest width, becoming gradually more 

 depressed forward; width at angle of mouth If in length 

 of head, its greatest width about 1J in its length; snout 

 short, 4 in the head. Top of head coarsely granular, 

 the granules forming strias in front, vermiculations pos- 

 teriorly, or in places more or less regular striae. Occip- 

 ital process truncate, its width at tip greater than its 

 length, the dorsal plate large, saddle-shaped, its bony 

 tubercles forming striae which are parallel with the 

 strongly convex margin of the " saddle;" opercular 

 bones granular striate, the humeral process with bony 

 tubercles. Fontanel nearly obsolete, the granular bony 

 surface being separated in front by thick skin which 

 covers an elongate area about seven times longer than 

 wide. 



Eye small, elliptical, 3 in snout, 12 in head, 6 in in- 

 terocular. A narrow flap of skin across the snout con- 

 necting the posterior nasal openings. 



Maxillary barbels reaching beyond humeral process; 



