128 



MEMOIRS OF THE CARNEGIE MUSEUM 



or chin, sometimes expanded downward behind gill-opening; a more or less evident 

 dark streak across the nuchal plate; a conspicuous dark band across the back and 

 dorsal fin, extending forward below to the axil; one or two more or less evident 

 dark blotches on the back of the tail, the anterior over the anal; fins colored like 

 the adjoining portions of the body. 



Agmus 4 gen. nov. 

 Agmus Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 379. 



Type, Agmus scabriceps Eigenmann and Eigenmann (Plate IV). 



This genus differs from Bunocephalus in the great development of tubercles 

 about the head, which at the occiput is almost as high as it is wide: the depth of the 

 head at this point equals the distance of the pectoral from the snout. This genus 

 reaches the limit of divergence from Aspredo. 



1 1 . Agmus lyriformis sp. nov. (Plate III.) 

 Agmus lyriformis Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 



379 (name only). 



Type, 56 mm. Gluck Island. (Carnegie Museum Catalog of Fishes No. 

 1554.) 



Cotype, 49 mm. 



Rupununi. 



Fig. 25. Agmus lyriformis Eigenmann. 

 Type. C. M. Cat. No. 1554. 



(I. U. Cat. No. 11972.) 



The only other species of the genus is 

 A. scabriceps Eigenmann and Eigenmann 

 from Jutahy, differing from lyriformis in its 

 converging coracoid processes, mottled fins, 

 and extremely tubercular head. 



Head to end of occipital process 2.66 

 in its length; depth of head at occipital pro- 

 cess about equal to its width at gill-open- 

 ings. D. 5; A. 6. 



Nuchal plate with two high knobs; 

 dorsal plate with two small knobs, one on 

 either side in front of the dorsal; a trans- 

 verse ridge in front of the nuchal crest, 

 curved backward on the sides and ending 

 in a small knob; a knob over each eye, con- 

 tinued backward as a low crest with a small 



knob near its middle and a larger one in front of the large occipital knob, the two 



4 ayiibs, a craggy place. 



