452 DRIVER— THE LUCIOPIMELODIN^. 



D'Orbigny reported that the species is taken in the Parana from 

 latitude 26 degrees South to Buenos Aires. He reported it to be a 

 permanent resident at Corrientes, but at Buenos Aires it is migratory, 

 arriving in September and departing in March. 



Giinther in his Catalogue also placed it in the old genus Pime- 

 lodus which includes a number of different generic types. In a 

 short article on the Fish-fauna of Rio de la Plata/ Giinther briefly 

 describes Pimelodiis platanns. This species is without spots and it 

 is quite possible that it was included in the species patl concerning 

 which Valenciennes says (p. 178) : 



M. d'Orbigny nous dit que les taches varient a I'infini, et disparaissent 

 quelquefois entierement. 



Eigenmann and Eigenmann^ created the genus Liiciopimelodus 

 for pati and platanus placing the genus in the Pimelodinse. They 

 distinguished the genus by the flexible, non-spinous first dorsal and 

 first pectoral rays, the elongate, spatulate, depressed head, the nar- 

 row, short occipital process, and the fontanel confined to the frontal 

 portion of the head. 



Steindacher^ described Pirinampus agassizii. The relationship 

 of this species with pati was not recognized by Steindachner or 

 Eigenmann and Eigenmann, the latter placing it in a hypothetical 

 distinct but unnamed genus numbered XXII in their monograph on 

 the Nematognathi. This was later placed in a new genus, Perugia, 

 by Eigenmann and Norris. Steindachner described this species as 

 having a pungent dorsal spine, but Fisher^*^ shows that in a specimen 

 in the Carnegie Museum (N^o. 7251) there is evidence that the pun- 

 gency is due to the fact that the tip of the first dorsal ray is broken ofif. 



In his monograph on the Freshwater Fishes of British Guiana^^ 

 Eigenmann describes the new genus and species Megalonema platy- 

 cephalnm from the lower Potaro River of British Guiana. The 

 genus Megalonema differs from Lticiopiiiielodus in the shape of the 



''Ann. and Mag. Nat. Hist., Vol. VI., July, 1880, p. 10. 

 ^ Proc. Calif. Acad. Sci. (2), I., 1888, p. 122, and Occasional Papers Calif. 

 Acad. Sci., I., 1890, p. 106. 



9 6". B. Ak. IVien., LXXIV, 1876, Ichthyol. Beitr., IV, PI. 12. 

 ^'^ Ann. Carnegie Mus., XI, 1917, p. 407. 

 ^1 Mem. Carnegie Mtts., V, 1912, p. 150. 



