EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 365 



222. Deuterodon pinnatus Eigenmann. (Plate LIII, fig. 2.) 

 Deuterodon pinnatus Eigenmann, Ann. Carnegie Mus., VI, 1909, 26; Repts. Prince- 

 ton Univ. Exp. Patagonia, III, 1910, 431. 



Type, 62 mm. Amatnk. (Carnegie Museum Catalog of Fishes No. 1046.) 



Cotypes, twenty-five specimens, 32-75 mm. Amatuk. (C. M. Cat. No. 

 1047a-e; I. U. Cat. No. 11738.) 



Cotypes, two specimens, 36-40 mm. Konawaruk. (C. M. Cat. No. 1048; 

 I. U. Cat. No. 11739.) 



Cotypes, nineteen specimens, 21-43 mm. Warraputa. (C. M. Cat. No. 

 1049a-c; I. U. Cat. No. 11740.) 



Distinguished from all other Tetragonopterids by the pinnate black markings 

 of the sides. 



Head 4-4.3; depth 2.5-2.7; D. 10 or 11; A. 24-25, rarely 27; scales 6-36 or 

 37-4 or 5. 



Compressed, subrhomboidal; profile slightly depressed over the eye; preventral 

 area rounded; the scales large, a nearly regular median series; postventral area 

 narrowly rounded, the anus directly in front of the anal; predorsal area narrowly 

 rounded, with a median series of about nine scales. 



Occipital process triangular, not quite one-fourth of the distance from its base 

 to the dorsal, bordered by three scales; interorbital convex; fontanels narrow, the 

 anterior shorter than the parietal; second suborbital deep, leaving a wide naked 

 area; maxillary about 3.5 in the head; three or four teeth in the outer row of the 

 premaxillary ; five graduated teeth in the inner series, expanded at top, the denticles 

 in a crescent, the middle one not notably larger or longer than the others; three 

 or four similar teeth in the maxillary; dentary with eight to ten graduated teeth, 

 similar to those of the premaxillary, but with longer median point; all the teeth 

 brown-tipped. 



Gill-rakers short, 6+10. 



Ventrals in advance of the vertical from the dorsal; origin of dorsal in the 

 middle or slightly in advance of the middle, its highest ray 3.75 in the length; 

 twelfth anal ray two-fifths to about half as high as the highest, the anal margin 

 concave or not; pectorals reaching slightly beyond origin of ventrals, ventrals 

 not quite to anal. 



Cheeks and opercles punctate; a well-developed humeral spot in a vertical 

 humeral band ; a second band in front of the dorsal, shading into the much punctate 

 sides; a black median line, from which black streaks branch along the septa of the 

 muscles at every other myotome; a conspicuous, large caudal spot, not continued 



