138 OSTARIOPHYSI, 
6. CONORHYNCHUS, Bleek., 1863 *. 
Conorhynchus, Giinth. Cat. Fish. v. p. 185 (1864). 
Teeth feeble or absent ; adipose fin rather short; in other respects similar to Pimelodus. 
Three species, ranging from Mexico to Brazil. 
1. Conorhynchus nelsoni. 
Conorhynchus nelsoni, Everm. & Goldsborough, Bull. U.S. Fish. Comm. xxi. p. 140, fig. 1 (1902). 
Snout long, conical ; posterior part of head naked, rugose; barbels short. DorsalI 6. Anal 17. Caudal 
forked. 
Hab. Mexico, Rio Usumacinta in Chiapas. 
7. AMIURUS, Rafin., 1820. . 
Ictalurus, Amiurus, Villarius, and Istlarius, Jord. & Everm. Bull. U.S. Nat. Mus. xlvii. 1896— 
1900, pp. 138, 135, 2799, & 31388. 
Body elongate ; mouth terminal or subterminal ; jaws with villiform teeth in bands, the premaxillary band of 
teeth of nearly equal breadth throughout, sometimes with a slight posterior extension on each side; 
palate toothless; nostrils remote from each other, the posterior with a barbel; barbels eight. Dorsal 
fin with a spine and 6 branched rays; adipose fin short; anal of moderate length or rather elongate ; 
ventrals 8- or 9-rayed. 
About 20 species from North and Central America and one from China. 
Synopsis of the Mexican and Central-American Species. 
I. Caudal fin forked or deeply emarginate. 
A. Occipital process notched at the apex for the reception of the anterior point of the second 
interneural. (IcTaLuRvs.) . 
Anal with 28 to 82 rays; pectoral spine about 4 the length of head, its inner 
edge with 9-12 serre; maxillary barbel extending to base of pectoral ; 
silvery, back darker i 1. meridionalis. 
Anal with 25 to 30 rays; pectoral spine nearly 3 the length of head, its inner 
edge with 10 or 11 serre; maxillary barbel extending nearly to middle of 
pectoral; silvery, back darker, sides usually with small, round, dark spots. 2. punctatus. 
B. Occipital process pointed or truncated posteriorly, not or scarcely reaching the second 
interneural. (Havsror.) 
1. Pectoral spine with inner edge distinctly serrated. 
Anal with 82 to 87 rays; pectoral spine about 4 the length of head, its inner 
edge with 5 or 6 strong serre; maxillary barbel extending to basal part 
or middle (young) of pectoral . 2. 2. 1. ee ew wee we ee 8 furcatus. 
Anal with 24 to 29 rays; pectoral spine about # the length of head, its inner | 
edge with 7 to 9 serre ; maxillary barbel extending to middle of pectoral . 4. lupus. 
Anal with 19 to 22 rays; pectoral spine ? the length of head, its inner edge 
with 10 to 12 rather short projections, some of which are bifid; maxillary 
barbel extending nearly to middle of pectoral . . . . . . 1... 5. pricei. 
* Preoccupied in Coleoptera (Motschulsky, 1860). 
