114 OSTAEIOPHYSI. 



6. OXYLORICARIA, Bleek. 

 O.vyloncari<i, Regan, Trans. Zool. Soc. xvii. 190i, p. 297. 



Diflers from Lor'uai-la in the uiimorous, setiform teeth and the absence of an orbital notch. 

 Seven species from Panama and South America. 



1. Oxyloricaria panamensis, Eigenm. 



Loricaria aurea, Steind. Deukschr. Ak. Wien, Ixxii. 1902, p. 138, t. 5. fig. 1. 

 Oxi/Ioricaria panmnensis , Regan, Trans. Zool. Soc. xvii. 1901, p. 301. 

 Hodj- slender, elongate ; snout produced as a rostrum. 



Ilah. Panama. — Colombia, Rio Magdalena. 



Fam. 2. SILUEID^. 



This is one of the largest families of fishes, comprising over 1000 species, 

 and is nearly cosmopolitan. The Mexican and Central- American Siluiidoe may be 

 recognized by the naked body, the presence of two to four pairs of barbels, the short 

 anteriorly phaced dorsal fin, the tirst ray of which is a more or less strong spine, the 

 presence of an adipose fin, and the spiny outer ray of the pectoral fins. 



In Mexico and Central America there are about sixty species, comprising (1) marine 

 Cat-fishes of the genera Arius, Oaleiclitliys, and JElimchthys, most of the species of 

 which seem to enter fresh-waters ; (2) fishes of the South-American fresh-water genera 

 Rhamdia, Fimelodns, and Conorhynchus ; and (3) the North-American fresh-water 

 types, Amiurus and Lejyfoj^s. 



Syno])sis of the Mexican and Central- American Genera. 



I. Nostrils close together ; teeth on the palate ; no nasal barbels ; ventral fins with G rays. 



A. Teeth on tlie palate villiform. 



Four barbels 1. ^EnJiiicHTiiys. 



Six barbels 2. Galisichthys. 



B. Teeth on the palate granular or obtusely conical ; six barbels ... 3. Amus. 



II. Nostrils well separated; palate toothless. 



A. No nasal barbels ; barbels 6 ; ventral fins with 6 rays. 



1. Adipose fin long; jaws with well-developed teeth. 



Dorsal fin-spine slender, flexible; occipital process not nearly reaching the 



dorsal fin . 4. RiiAiiniA. 



Dorsal fin-spine pungent ; occipital process extending to shield at base of 



spineof dorsal fin .5. Pimelouus. 



2. Adipose fin rather short, shorter than the anal ; teeth in the jaws 



feeble or absent .0. Co.noiuiynchus. 



