132 
OSTARIOPHYSI. 
pectoral spine, which has the inner edge serrated and measures 3 to 3 of the length of the fin or about 4 
the length of head. Ventrals inserted behind the last ray of dorsal, extending 3 to 2 of the distance 
from their base to the origin of anal. Caudal deeply notched, the lower lobe rounded. Least depth of 
caudal peduncle about 3 the length of head or of the distance from anal to base of caudal. Brownish ; 
usually a blackish lateral stripe; fins dusky, the dorsal with a pale band near the base. 
Hab. Costa Rica, Shirures (H. Pittier); Panama! ®.—Western Ecuapor (Rosenberg). 
Here described from four specimens, measuring 200 to 280 mm. in total length. 
Probably records of this species from Southern Mexico refer to &. guatemalensis. 
6. Rhamdia petenensis. (Tab. XXII. fig. 1.) 
Pimelodus petenensis, Ginth. Cat. Fish. v. p. 126 (1864) *. 
Rhamdia petenensis, Jord. & Everm, Bull. U.S. Nat. Mus. xlvii. 1896, p. 153”. 
Depth of body 53 in the length, length of head 43. Breadth of head 1} in the length, length of snout 24, 
diameter of eye 53, interorbital width 38. Jaws nearly equal anteriorly ; width of mouth 2 the width of 
head. Maxillary barbel extending to origin of adipose fin. Head covered with smooth skin ; occipital 
process extending about 3 of the distance from its base to the origin of dorsal. 8 gill-rakers on the 
lower part of anterior arch. Dorsal 16; spine slender, fin rounded. Length of adipose fin 24 in 
the length of the fish. Anal 12. Humeral process extending to middle of pectoral spine, which is 
2 to ? the length of the fin and nearly 4 the length of head. Ventrals inserted behind the last dorsal 
ray, extending 2 of the distance from their base to the origin of anal. Caudal deeply notched. Least 
depth of caudal peduncle 1? in the length of head and 14 in the distance from anal to base of caudal. 
Brownish ; an indistinct dark lateral stripe; dorsal dusky, with a pale band near the base. 
Hab. Guatemata, Lake Peten ! (Salvin). 
Here described from the type, a specimen measuring 200 mm. in total length. 
7. Rhamdia guatemalensis. 
Pimelodus guatemalensis, Giinth. Cat. Fish. v. p. 122 (1864) *. 
Rhamdia guatemalensis, Jord. & Everm. Bull. U.S. Nat. Mus. xlvii. 1896, p. 1527, 
Rha 
mdia oaxace, Meek, Publ. Columbian Mus., Zool. v. 1904, p. 20, t. 5°. 
Depth of body 5 to 63 in the length, length of head 34 to 42. Breadth of head 14 to 12 in its length, length 
of snout 2? to 3, diameter of eye 5 to 73, interorbital width 22 to 31. Lower jaw nearly as long as 
the upper; width of mouth # to 2 the width of head. Maxillary barbel extending to origin or middle 
of adipose fin. Head covered with smooth skin ; occipital process extending nearly 3 the distance from 
its base to the origin of dorsal. 5 to 7 gill-rakers on the lower part of anterior arch. Dorsal I 6; spine 
slender, fin rounded. Length of adipose fin 22 to 3 in the length of the fish. Anal 11-13, when laid 
back reaching the vertical from the end of adipose fin. Humeral process extending about to middle of 
pectoral spine, which has the inner edge serrated and measures from less than 2 to more than 3 the 
length of the fin, or 2 to 4 the length of head. Ventrals inserted behind the vertical from last ray of 
dorsal, extending 2 to # of the distance from their base to the origin of anal. Caudal deeply notched, 
the lower lobe rounded. Least depth of caudal peduncle 2 to 23 in the length of head or 14 to 2 in the 
distance from anal to base of caudal. Brownish; usually a blackish lateral stripe; fins usually more or 
less dusky, the dorsal with an indistinct pale band near the base. 
Hab. SournerN Mexico, Rio Blanco%, Rio Papaloapam%, Tequesixtlan in Oaxaca 
(Gadow); British Honpuras, Stann Creek (Robertson) ; GuaTEMALA, Huamuchal! 
(Salvin). 
