138 OSTAKIOPHYSI. 



G. CONORHYNCHUS, Bleek., 1863*. 



ConorlnjiicJiits, Giintli. Cat. Fish. v. p. 135 {18G4). 



Teutli feeble or al)sent ; adipose fin rather short ; in other respects similar to Plmdodas. 

 Three species, ranging from Mexico to Brazil. 



1. Conorliynclius nelsoni. 



('onor/ii/nchus nelsoni, Everrn. & Goldsborouglij Bull. U.S. Fisli. ConiDi. xxi. p. 140, fig. 1 (1902). 



Snout long, conical ; posterior part of head naked, rngose ; barbels short. Dorsal I 6. Anal 17. Caudal 

 forked. 



Ilab. Mexico, Rio Usumacinta in Chiapas. 



7. AMIURUS, Rafin., 1820. 

 Ictahtrus, Amiurus, ViUur'iiis, and htlnrlus, Jord. & Everm. Bull. U.S. Nat. j\lus. xlvii. 189(1- 

 1900, pp. 133, 135, :.'799, & 3138. 



I'lody elongate ; mouth terminal or subtermiual ; jaws with villiform teeth in bands, the premaxillary band of 

 teeth of nearly equal breadth tliroughout, 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 0-rayed. 



About 20 species from North and Central America and one from China. 



Sijnojjsis of tlic Jle.vicaih and Central-American Species. 

 I. Caudal fiu forked or deeply emargiuate. 



A. Occipital process notclied at the apex for the reception of the anterior point of the second 



interneural. (Ictalukus.) 

 Anal with 28 to 33 rays ; pectoral spine about i the length of head, its inner 



edge with 9-12 serr;c ; maxillary Ijarbel extending to base of pectoral; 



silvery, back darker 1. meridionalis. 



Anal with 25 to 30 rays ; pectoral spine uearl}^ § the length of head, its inner 



edge with 10 or 11 scirte ; maxillary barbel extending nearly to middle of 



pectoral ; silvery, back darker, sides usually with small, round, dark spots . 2. puncialus. 



B. Occipital process pointed or truncated posteriorly, not or scarcely reaching the second 



interneural. (Haustou.) 

 1. Pectoral spine with inner edge distinctly serrated. 



Anal with 32 to 37 rays ; pectoral spine about ^ the length of head, its inner 

 edge with 5 or G strong scrrre ; maxillary ijarbel extending to basal part 

 or middle (young) of pectoral 3. furcatus. 



Anal with 21 to 29 rays; pectoral spiue about ;-; the length of head, its inner 



edge with 7 to 9 serrte ; maxillary barbel extending to middle of pectoral . 4. hums. 



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 5_ p^icgi 



* Preoccupied in Colcoptora (Motschulsky, 18G0). 



