HOPLIAS.—PIABUCINA. 167 
1. HOPLIAS. 
Macrodon (non Schinz), Miill. & Trosch. Hor, Ichthyol. iii. p. 6 (1845) ; Giinth. Cat. Fish. v. p. 281 
(1864) ; Jord. & Everm. Bull. U.S. Nat. Mus. xlvii. 1896, p. 330. 
Hoplias, Gill, Proc. U.S. Nat. Mus. xxvi. 1903, p. 1016. 
This genus comprises two species only, viz. H. microlepis from Panama and Western 
Ecuador, and the widely-distributed South-American J. trahira, Spix, which ranges 
from the Magdalena to the La Plata and which differs from its congener in having a 
broader head and somewhat larger scales. 
1. Hoplias microlepis. (Tab. XXVI. fig. 1.) 
Macrodon microlepis, Giinth. Cat. Fish. v. p. 282 (1864) *. 
Depth of body 33 to 5 in the length, length of head 33 to 33. Snout longer than eye, the diameter of which 
is 6 to 8 in the length of head; interorbital width 33 to 34 in the length of head. Mouth wide, the 
maxillary extending beyond the vertical from the posterior edge of eye ; teeth acutely conical, in a single 
series in the jaws, with some strong canines; teeth on the palatines in bands and on the vomer in two 
separate patches. 42 to 45 scales in a longitudinal series, 6 between middle of dorsal and lateral line, 
5 or 6 between lateral line and root of ventral fin, 11 across the back of the tail from one lateral line to 
the other. Dorsal 13-14, nearly in the middle of the length of the fish ; edge straight or slightly convex. 
Anal 10-11, rounded. Pectorals and ventrals of moderate length, rounded. Caudal rounded. Olivaceous, 
marbled with brownish, the marking sometimes forming a longitudinal band and vertival bars; fins with 
dark undulating stripes or series of spots. 
Hab. Panama, Rio Chagres! (Dow, Salvin).—Waestern Ecuapor (Festa). 
Here described from several specimens, including the types of the species, measuring 
up to 300 mm. in total length. 
2. PIABUCINA. 
Piabucina, Cuv. & Val. Hist. Nat. Poiss. xxii. p. 161 (1849); Giinth. Cat. Fish. v. p. 311 (1864) ; 
Jord. & Everm. Bull. U.S. Nat. Mus. xlvii. 1896, p. 332. 
This genus resembles //oplias in general form, in the structure and position of the 
fins, except that the caudal is emarginate instead of rounded, and in the absence of a 
fontanel in the cranial roof. 
About six species are known, from Panama, Ecuador, Colombia, Venezuela, and 
Guiana. 
1. Piabucina panamensis. 
Piabucina panamensis, Gill, Proc. Ac. Philad. 1876, p. 336’; Jord. & Everm. Bull, U.S. Nat. Mus. 
xlvii. 1896, p. 333°. 
Depth of body 4 in the length. Dorsal 10. Anal 12, 380 scales in a longitudinal series. A dark longi- 
tudinal band on the middle of the side; a dark spot on the base of the dorsal fin. 
Hab. Panama, Rio Tripoli}. 
This species may be identical with P. erythrinoides, C. & V., from Venezuela. 
