RHAMDIA. 131 
Depth of body 7 in the length, length of head 44. Breadth of head 13 inits length, length of snout 22, 
diameter of eye 53, interorbital width 4. Jaws nearly equal anteriorly ; width of mouth % the width of 
head. Maxillary barbel extending to origin of adipose fin *, Head covered with smooth skin; occipital 
process extending 4 of the distance from its base to the origin of dorsal. 11 gill-rakers on the lower 
part of the anterior arch. Dorsal I 6; spine slender, fin rounded. Length of adipose fin 22 in the 
length of the fish. Anal 13. Humeral process extending slightly beyond the middle of the pectoral 
spine, which is about $ the length of the fin and nearly } the length of head. Ventrals inserted behind 
the last dorsal ray, extending 3 of the distance from their base to the origin of anal. Caudal deeply 
notched. Least depth of caudal peduncle 23 in the length of head and 2} in the distance from the anal 
to the base of caudal. Brownish. 
Hab, Laxe Nicaracva? (Dow). 
Here described from the type, measuring 190 mm. in total length. 
4. Rhamdia boucardi. (Tab. XX. fig. 3.) 
? Rhamdia depressa, Barbour & Cole, Bull. Mus. Comp. Zool. 1. 1906, p. 155, t. 1? F. 
Pimelodus boucardi, Regan, Ann. Mag. Nat. Hist. (7) xix. 1907, p. 258’, . 
Depth of body 64 in the length, length of head 4. Breadth of head 1} in its length, length of snout 23. 
diameter of eye 6, interorbital width 3. Lower jaw nearly as long as the upper ; width of mouth 2 the 
width of head. Maxillary barbel extending to origin of adipose fin. Head covered with smooth skin ; 
occipital process rather strong, extending 3 the distance from its base to the origin of dorsal. 12 or 13 
gill-rakers on the lower part of the anterior arch. Dorsal I 6, the spine slender, the fin rounded. 
Adipose fin 3 the length of the fish. Anal 14; when laid back nearly reaching the vertical from 
the end of adipose fin. Pectoral spine with serrated inner edge, about 2 the length of the fin and } the 
length of head; humeral process long, nearly reaching the middle of the fin. Ventrals originating nearly 
below the last dorsal ray, extending more than 2 of the distance from their base to the origin of anal. 
Caudal deeply notched, the lobes rounded, the lower the larger. Least depth of caudal peduncle 3 in the 
length of head, and 23 in the distance from anal to base of caudal. Blackish. 
Hab. Mexico, Yucatan} (Boucard). 
Here described from the type, a specimen measuring 190 mm. in total length. 
5. Rhamdia wagneri. 
Pimelodus cinerascens (non Ginth.), Kner & Steind. Abhandl. Bayern. Akad. x. 1865, p. 49°. 
Pimelodus wagneri, Giinth. Trans. Zool. Soc. vi. 1868, p. 474°. 
Rhamdia bransfordi, Gill, Proc. Ac. Philad. 1876, p. 337°. 
Rhamdia wagneri, Jord. & Everm. Bull. U.S. Nat. Mus. xlvii. 1896, p. 151*. 
Depth of body about 6 in the length, length of head 43 to 43. Breadth of head 1} to 14 in its length, length 
of snout 22 to 22, diameter of eye 6 to 7, interorbital width 22 to 3. Lower jaw nearly as long as the 
upper ; width of mouth about 2 the width of head. Maxillary barbel extending about to the origin of 
adipose fin. Head covered with smooth skin ; occipital process extending 3 of the distance from its base 
to the origin of dorsal. 7 to 9 gill-rakers on the lower part of anterior arch. Dorsal I 6; spine slender, 
fin rounded. Length of adipose fin 23 to 3 in the length of the fish. Anal 10-12, when laid back 
nearly reaching the vertical from end of adipose fin. Humeral process extending about to the middle of 
* As described by Giinther. Both barbels are now broken off in the type, the longest reaching the middle 
of the dorsal. 
+ Rhamdia depressa is probably the same as R, boucardi, but the description is insufficient and the figure bad. 
S 2 
