RHAMDIA. 135 
13. Rhamdia brachycephala. (Tab. XXII. fig. 2.) 
Pimelodus brachycephalus, Regan, Ann. Mag. N. H. (7) xix. 1907, p. 258°. 
Depth of body 53 to 63 in the length, length of head 53 to 54. Breadth of head 11 in its length, length of snout 
2% to 3, diameter of eye 5 to 6, interorbital width 3 to 33. Lower jaw a little shorter than the upper ; 
width of mouth 3 to 2 the width of head. Maxillary barbel extending to the basal part of pectoral. 
Head covered with smooth skin; occipital process slender, extending about 1 of the distance from its 
base to the origin of dorsal. 6 to 8 gill-rakers on the lower part of the anterior arch. Dorsal I 6, the 
spines slender, the fin rounded. Length of adipose fin 3} to 32 in the length of the fish. Anal 12-13, 
when laid back sometimes reaching the vertical from end of adipose fin. Pectoral spine with serrated 
inner edge, about 2 the length of the fin and 2 the length of head; humeral process extending to or 
beyond the middle of the spine. Ventrals originating behind the dorsal, extending 4 to 3 the distance 
from their base to the origin of anal. Caudal moderately notched, the lower lobe rounded and rather 
shorter than the upper. Least depth of caudal peduncle $ or more than 2 the length of head, 12 to 14 
in the distance from anal to base of caudal. Brownish. 
Hab. Guatemata, Rio Nacasil 1 (Salvin). 
Here described from the types, six specimens, measuring up to 190 mm. in total 
length. 
14. Rhamdia underwoodi, sp.n. (Tab. XXIII. fig. 4.) 
Depth of body 53 to 6 in the length, length of head 42 to 5. Breadth of head 14 to 1} in its length, length 
of snout 22 to 24, diameter of eye 6 to 7, interorbital width 3. Lower jaw scarcely shorter than the 
upper ; width of mouth 4 to 3 the width of head. Maxillary barbel extending to posterior end of pectoral 
fin. Head covered with smooth skin ; occipital process extending + or 4 of the distance from its base to 
the origin of dorsal. 7 or 8 gill-rakers on the lower part of the anterior arch. Dorsal I 6 (exceptionally 
17); spine slender, fin rounded. Length of adipose fin 32 to 43 in the length of the fish, Anal 11-12. 
Humeral process short, not extending to middle of pectoral spine, which has the inner edge serrated 
and measures about 2 the length of the fin and 3 to 2 the length of the head. Ventrals inserted behind 
the last ray of the dorsal, extending 4 to 2 of the distance from their base to the origin of anal. Caudal 
moderately notched. Least depth of caudal peduncle 12 to 2 in the length of head and 14 to 12 in the 
distance from anal to base of caudal. Blackish grey. 
Hab. Costa Rica, Juan Vifias (Underwood). 
Four specimens, the largest 100 mm, in total length. 
15. Rhamdia salvini, (Tab. XXIII. fig. 2.) 
Pimelodus salvini, Giinth. Cat. Fish. v. p. 180 (1864) *. 
Rhamdia salvini, Jord. & Everm. Bull. U.S. Nat. Mus, xlvii. 1896, p. 152. 
Depth of body 64 in the length, length of head 52. Breadth of head Gy in its length, length of snout 23, 
diameter of eye 6, interorbital width 31. Jaws nearly equal anteriorly; width of mouth 2 the width of 
head. Maxillary barbel extending a little beyond middle of pectoral. Head covered with smooth skin ; 
occipital process short, triangular, extending 4 of the distance from its base to the origin of dorsal. 
7 gill-rakers on the lower part of anterior arch. Dorsal I 6; spine slender, fin rounded. Length of 
adipose fin 34 in the length of the fish. Anal 12. Humeral process extending beyond the middle of the 
pectoral spine, which is about 3 the length of the fin and 3 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 moderately 
notched. Least depth of caudal peduncle 14 in the length of head and 2 in the distance from anal to 
base of caudal. Brownish. 
