ELURICHTHYS, 115 
B. Posterior nostril with a barbel; barbels 8; ventral fins with 8 or 9 rays. 
Premaxillary band of teeth of equal breadth throughout, or sometimes very 
slightly produced backwards at the sides ; lower jaw not projecting . . 7. Amrurus. 
Premaxillary band of teeth with a well-developed posterior extension on each 
side; lower jaw somewhat projecting. . . . . . . . . « « « 8 Lmprors. 
1. AALURICHTHYS, Baird & Girard, 1854.. 
Ailurichthys, Giinth. Cat. Fish. v. p. 177 (1864). 
Felichthys (Swainson), Jord. & Everm. Bull. U.S. Nat. Mus. xlvii. 1896, p. 116. 
Body elongate. Mouth terminal or subterminal; jaws with villiform teeth in bands ; vomerine and palatine 
teeth ; nostrils close together, the posterior with a flap; a pair of maxillary and a pair of mental barbels. 
Parieto-occipital with a process which extends posteriorly to the small basal shield of the dorsal spine. 
Dorsal fin with a strong spine and 7 branched rays; adipose fin short; anal moderate or rather long : 
ventral fins 6-rayed ; caudal deeply forked. 
Eight species from the Coasts and Rivers of America. 
It seems most useful to deal here with the whole genus and not to omit the two 
species (A. bahiensis and A. bagre) which are not known to range so far north as 
Central America, but which may do so. 
Synopsis of the Species. 
I. Occipital process of nearly equal breadth throughout, with convex lateral edges *; spine of 
dorsal fin not bearing a filament; about 14 gill-rakers on the lower part of the anterior 
arch. 
A. Vomerine patches of teeth separate, nearly equal in length and breadth 
to the palatine patches; occipital process not broader than long ; 
anal of 26 or 27 rays . 2. . sw oe » oe ee ee 61. panamensis. 
B. Vomerine patches of teeth united, consider ably broader than the palatine patches ; occipital 
process broader than long. 
Breadth of occipital process 2 or nearly 2? the length of head ; anal of 28 rays, 
produced anteriorly, the longest ray, when laid back, reaching beyond 
the end of the base of the fin. 2. 2. 2 2 1 2 we 6 ee ee ww  SCUtatuS. 
Breadth of occipital process } the length of head; anal of 29 or 80 rays, the 
longest, when laid back, not reaching the end of the base of the fin . . 3. asthmensis. 
II. Occipital process narrowed posteriorly, with concave or straight lateral edges ; spine of dorsal 
fin bearing a long filamentous ray; not more than 10 gill-rakers on the lower part of the 
auterior arch. 
A. Distance from tip of snout to origin of dorsal nearly 4 the length of the fish (to base 
of caudal). 
1. Pectoral spine 2 to 2 as long as the head. 
Anal of 22 to 24 rays, the longest nearly as long as or shorter than the base 
of the fin; dorsal filament not reaching the adipose fin . . . . « . 4 marinus. 
* In the species of this section the occipital process has the appearance of a separate nuchal shield. 
Q2 
