SOUTH AMERICAN NEMATOGNATHI. 93 



66. Tachisurus gulosus. 



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

 i, 1888, 146 (Panama). 



Elongate slender, the width scarcely less than the 

 depth. Head broad, strongly depressed, the profile, to 

 the tip of the snout nearly straight; greatest width of the 

 head 1| in its length; depth at base of occipital process 

 about 2 in the length of head. Occipital process about 

 as broad as long, obtusely keeled. Fontanel very narrow, 

 its center above the posterior margin of the eye, con- 

 tinued as a groove backward. Posterior portion of the 

 head rugose. Fontanel anteriorly margined by a bony 

 ridge; a ridge extending obliquely between it and the 

 eye; opercle faintly striate; sides of head and snout with 

 reticulating canals. 



Eye oblique, its center over the posterior end of the 

 mandible and about on a level with the angle of the 

 mouth, its diameter 2^ in snout, 8 in head, 5 in the 

 interocular distance. 



Maxillary and postmental barbels reaching to the 

 middle of the pectoral or shorter, mental barbels to 

 near the base of the pectoral. 



Jaws subequal, very thin; the intermaxillary band of 

 teeth very shallow in the middle; vomerine teeth none; 

 distance between palatine patches of teeth 1| diameters 

 of the eye; the teeth obtusely conical, 

 in about three series in front, in a 

 single series behind; mandibulary band 

 of teeth little shallower than the inter- 

 maxillary band. 



Gill-membranes united, and with a free margin. Gill- 

 rakers 1| times as long as the eye, 12+30. 



Pectoral pore large; vertical series of pores conspic- 

 uous. 



Distance of dorsal from snout 21 in the length; dorsal 



