678 EIGENMANN— NEW FISHES FROM 



same rate in all specimens so that in two specimens of the same size, 

 one may have an apparent spine while in the other it may be hidden. 

 The smaller ones in which the spine is especially well developed may 

 not be distinguishable from A. unifasciatus.) Dorsal spine very 

 slightly, if at all, produced, almost two thirds the length of the 

 head ; distance between snout and dorsal 2.66-2.75 in the length ; 

 teeth of the premaxillary all single pointed, or one or two pairs 

 bicuspid. Sides variously spotted, a V-shaped light area in front 

 of the dorsal, frequently a bar across the sides below the adipose as 

 in A. unifasciatus; base of caudal and one or two rows of spots 

 parallel with the margin. 



The paratypes differ but little from each other, and the speci- 

 mens from the Ducho are very similar to them. 



LORICARIID.E. 



5. Hemiancistrus Wilsoni spec, no v. 



For Mr. Charles Wilson who made large collections in the Rio 

 Truando, a tributary of the Rio Atrato. 



7570 C. ; 13921 L, eight, 90-133 mm. Truando. Wilson. The 

 largest the type. Similar to H. holostictiis from the San 

 Juan. 



Head 3-3.25 ; depth 4.5-5 ; D. I, 7 ; A. I, 4 ; 27 scutes, six or 

 seven between the dorsals, 11+3 between the anal and caudal ; 

 depth at tip of occipital equals snout and half the eye ; width above 

 base of pectoral almost equal to length of the head; mandible 3-3.6 

 in the interorbital ; eye 4.25 in snout, 3 in interorbital, 7 in the head ; 

 interorbital with 3 minute spines or none. 



Occipital with a high keel," median plate behind it feebly bicari- 

 nate, plates of the sides well carinate; dorsal spine equal to head and 

 two or three scutes behind it, reaching to the adipose spine or the 

 plate in front of it, the last ray reaching the spine of the adipose; 

 caudal deeply emarginate, the lower lobe considerably longer, 2.2 

 in the length; the middle rays about 1.4 in the lower; ventral sur- 

 face in a specimen about 115 mm. long mostly naked, in the larger 

 ones granulose except in a small area in front of the ventral. 



