41 2 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [70] 



73. PACHYURJS FRANCISCI. 



Lepipterus francisci Cuv. & Val., Hist. Nat., v, 152, plate 113, 1830 (Rio Sao Fran- 

 cisco). 



I'aehynrus francisci Giinther, Cat. Fish. Brit. Mus., ii, 281, 1860 (copied). 



Pachyurus corvina (Reiuliardt MS.), Liitken, Velhas-Flodens Fiske, xx, 1875 (Rio 

 das Velhas). 



Habitat. — Rivers of Brazil. 



We kuow this species from descriptions only. 



74. PACHYURUS BONARIENSIS. 



Pachyurus bonariensis Steindachner, Iclithyol. Beitr., viii, 8, 1870 (Rio de la Plata). 



Habitat. — Basin of the Rio de la Plata. 



We have examined three specimens of this species in the Museum of 

 Comparative Zoology. Two of them, each about a foot in length, are 

 from Buenos Ayres, the other from Rosario. 



75. PACHYURUS SCHOMBURGKI. 



Pachyurus schoniburgki Giinther, Cat. Fish. Brit. Mus., ii, 282, 1860 (Rio Capin; Ca- 

 rife; Para). Steindachner, Ichthyol. Beitriige, viii, 11, 1879 (Pari; Carneta; 

 Obidos; Lake Saraca; Rio Negro; Rio Branco). 



Pachyurus nattereri Steindachner, Beitr. zur Kenntn. der Sciaen. Brasil., 10, plate iii, 

 1863 (Rio Bianco ; Rio Negro). 



Habitat. — Rivers of Brazil. 



This species is known to us from descriptions only. We have failed 

 to recognize it in the collections at Cambridge. We follow Steindachner 

 in regarding his Pachyurus nattereri as a synonym of schomburgki. 



Genus XVI.— PACHTPOPS. 



Pachypops Gill, Proc. Ac. Nat. Sci. Phila., 1861, 87 (trifilis). 



Type : Micropogon trijilis Midler & Troschel. 



This genus, like Pachyurus, is composed entirely of fresh-water spe- 

 cies, inhabiting the Amazon region. It differs from Pachyurus only in 

 the presence of small barbels at the chin, and in some individuals these 

 appendages may be rudimentary or even wanting. For this reason Dr. 

 Steindachner has proposed to regard this character as of no systematic 

 importance, and to place these species in the subgenus Lepipterus under 

 Pachyurus. But unless it can be shown that the Pachyuri sometimes 

 possess barbels, it seems to us better to retain the two groups as dis- 

 tinct genera. 



ANALYSIS OF SPECIES OF PACHYPOPS. 



a. Dorsal rays X-I, 25 to 27 ; body without conspicuous dark brown spots; caudal 

 rhombic ; teeth all equally small. 

 h. Maxillary scarcely reaching front of eye, its length 4 to 4-J in head : barbels 3 ( 

 minute (sometimes obsolete) ; snout prominent, blunt, 2f in head ; eye very 

 large, 3 in head ; mouth very small, overlapped by the turgid preorbital ; teeth 

 small, equal ; gill-rakers very small ; soft dorsal and anal completely scaled ; 

 pectorals 1^ in head ; caudal rhombic, 1£ in head; second anal spine 2^ in head ; 



