412 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [70] 
73. PACHYURUS PRANCISCI. 
Lepipterus francisci Cuy. & Val., Hist. Nat., v, 152, plate 113, 1830 (Rio Sao Fran- 
cisco), 
Pachyurus francisci Giinther, Cat. Fish. Brit. Mus., ii, 281, 1860 (copied). 
Pachyurus corvina (Reinhardt MS.), Liitken, Velhas-Flodens Fiske, xx, 1875 (Rio 
das Velhas). 
Habitat.—Rivers of Brazil. 
We know this species from descriptions only. 
74. PACHYURUS BONARIENSIS. 
Pachyurus bonariensis Steindachner, Ichthyol. Beitr., viii, 8, 1879 (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 schomburgki Giinther, Cat. Fish. Brit. Mus., ii, 282, 1860 (Rio Capin; Ca- 
rife; Pard). Steindachner, Ichthyol. Beitrige, viii, 11, 1879 (Para; Cameta; 
Obidos; Lake Saraca; Rio Negro; Rio Branco). 
Pachyurus nattereri Steindachner, Beitr. zur Kenntn. der Scien. Brasil., 10, plate iii, 
1863 (Rio Branco; 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 natterert as a synonym of schomburgki. 
Genus XVI.—PACHYPOPS. 
Pachypops Gill, Proc. Ac. Nat. Sci. Phila., 1861, 87 (trifilis). 
TyPE: Micropogon trifilis Miiller & 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. [or 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. P 
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. 
b. Maxillary scarcely reaching front of eye, its length 4 to 4} in head; barbels 3, 
minute (sometimes obsolete); snout prominent, blunt, 24 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 14 in head ; caudal rhombic, 14 in head; second anal spine 2} in head ; 
