DRIVER— THE LUCIOPIMELODIN^. 455 



Megalonema pauciradiatum Eigenmann, spec. nov. 



15029, I. U. M., four, the largest the type, 28-38 mm. Villa Rica. 

 Anisits. 



Head 4 ; depth 5.33 ; A. 9 ; adipose 4.75 in the length ; eye 4 in the 

 head, .75 in the interorbital ; maxillary barbel reaching middle or tip 

 of dorsal, postmental a little beyond tip of pectoral ; teeth in very 

 narrow bands ; snout depressed, width of head at the rictus 2 in the 

 length; depth of head nearly two-thirds its length; fontanel reaching 

 base of occipital crest which is minute, reaching only about one-sixth 

 of the way to the dorsal fin ; distance between snout and dorsal 

 2-2.66 in the length ; first dorsal ray slender, a little longer than the 

 head, extending beyond all the rest when depressed ; ventrals and 

 base of third dorsal ray about equidistant from snout ; first pectoral 

 ray slender, reaching the ventrals, the latter not to the anal ; caudal 

 peduncle 5 in the length. 



Air-bladder transverse, about three times as wide as long. 



Pale, without any conspicuous markings. 



The type is a female with mature eggs nearly a millimeter in 

 diameter. While the specimens at hand have probably not reached 

 full size, the largest is sexually mature. 



This species differs from Megalonema platanum and Lnciopiine- 

 lodus pati of the Plata basin in having but nine anal rays while they 

 have twelve. 

 Perugia agassizii (Steindachner). 



Pirinampus agassizii Steindachner, Sb. Ak. Wicn, LXXIV, 

 1876; Ichthyol. Beitr., IV, 57, pi. 12 (Para) ; Vaillant, Bull. 

 Soc. Philoiii., series 7, IV, 153, 1880 (Calderon). 



^ agassizii Eigenm. & Eigenm., Occasional Papers Calif. Acad. 

 Sci., I, p. 183, 1890 (Amazons). 



Perugia gen. nov. Eigenmann & Norris, Revista Miiseu Paulista, 

 IV, p. 355, 1900. 



Luciopimelodus agassizii Eigenmann, Repts. Princeton Univ. 

 Exped. Patagonia, III, 1910, p. 383 (name only). Fisher, 

 Ann. Carnegie Mus., XI, 1917, p. 407 (Para). 



Habitat: Amazons. 



