ElGENMANN : THE EXPEDITION TO BRITISH GUIANA. 11 



Closely allied to brunnea. 



Head very little less than five in the length ; width of head 1.5 in 

 its length; eye 5.5; interorbital 4; snout 2 in the head; width of 

 first anal ray 5 in its distance from the caudal ; 124-15 scutes, the 

 lateral ridges almost completely united on the last seven scutes. 



Lips well developed, with a marginal series of fringes, which is inter- 

 rupted in the middle in front, and with rather long warts. Lips not 

 nearly reaching gill-opening. Seven or eight teeth in each side of 

 each jaw. Free portion of the barbel about equal to the eye. 



Head without ridges, plates in front of the dorsal but faintly keeled. 

 Orbital notch shallow, narrowly rounded. 



Anal plate bordered by three plates in front ; the ventral buckler 

 formed of seven plates ; about three series of plates between the lateral 

 plates, these with the lateral plates forming in the posterior part regu- 

 lar transverse scutes, the plates becoming more numerous and less 

 regular in front. Armature of belly truncate in front, not extending 

 quite to the anterior angle of the gill-opening. 



Pectorals, slightly emarginate, the inner angle rounded, extending 

 to the second fourth of the ventrals ; ventral rays graduate, the outer 

 ray scarcely prolonged, reaching to the base of the last anal ray. 



Pores of the head and on the body to below the dorsal jet-black ; 

 obscure cross-bands ; that below the base of the dorsal and that below 

 its tip most prominent. No ocellus in front of dorsal. Dorsal spotted, 

 the submarginal spots most prominent. Pectoral, ventral, and anal 

 each with a broad submarginal dark band, base of caudal and the tips 

 exclusively of the upper ray black. Upper caudal ray much prolonged 

 forming 51 mm. of the total length of 142 mm. 



PYGIDIIDsE. 

 Genus Pygidium Meyen. 



Pygidium guianensis sp. nov. 



Type, 77 mm. (No. 1003 Carnegie Museum Catalog of Fishes.) 

 Aruataima Falls, Upper Potaro. 



Cotype, 34 mm. Waratuk, Lower Potaro (I. U. Cat. No. 11710). 



Cotype, 41 mm. Amatuk, Lower Potaro. 



Head 6 ; depth equals head in length ; D. 9 ; A. 7 ; eye 4 in snout, 

 9.5 in head. 



Head nearly as broad as long ; maxillary barbel reaching to tip ot 



