ALURICHTHYS.—GALEICHTHYS. 119 
Distance from tip of snout to origin of dorsal fin 34 to 4 in the length of the fish. Occipital process narrowed 
posteriorly, with straight or concave lateral edges. Maxillary barbel extending beyond the origin of 
anal fin; vomerine patches of teeth separate, much smaller than the palatine patches, with which they 
are subcontinuous; 4 gill-rakers and a few rudiments on the lower part of the anterior arch. Dorsal I 7; 
filamentous ray extending to the adipose fin. Anal 30-35; longest ray less than 3 the length of base 
of the fin, Pectoral spine ? the length of head. Silvery, back bluish, 
Hab, Atlantic Coast of South America; West Indies. 
Here described from three specimens, the largest 350 mm. in total length, 
2. GALEICHTHYS, Cuv. & Val., 1840. 
Galeichthys and Arius (part.), Cuv. & Val. Hist. Nat. Poiss. xv. pp. 28 & 52 (1840); Giinth. Cat. 
Fish. v. pp. 188 & 174 (1864). 
Sciedichthys (Bleek.), Selenaspis (Bieek.), Netuma (Bleek.), and Galeichthys, Jord. & Everm. Bull. 
U.S. Nat. Mus. xlvii. 1900, pp. 2757, 2760, 2764, & 2770. . 
Body elongate. Mouth terminal or subterminal; jaws with villiform teeth in bands; viiliform teeth on the 
palate ; nostrils close together, the posterior with a flap; a pair of maxillary and two pairs of mental 
barbels. Parieto-occipital produced into a process which extends to the basal shield of the dorsal spine. 
Dorsal fin with a strong spine and 7 branched rays; adipose fin short or of moderate length; anal of 
moderate length ; ventral fins 6-rayed; caudal deeply forked. 
A large number of species from the coasts of tropical and sub-tropical countries, 
most of them entering rivers freely. 
Synopsis of the Mexican and Central-American Species. 
I. Teeth present on vomer, palatines, and pterygoids, sometimes in separate patches, but in the 
adult usually forming a continuous band, the large subtriangular palato-pterygoid patches 
connected anteriorly by a transverse vomerine strip. 
A. A transverse membranous fold on the snout, connecting the posterior 
nostrils ; dorsal shield large, saddle-shaped . . . . .. . . . «OL. dovii. 
B. No membranous fold connecting the posterior nostrils. 
1. Dorsal shield subpentagonal, large, its length in the middle line 
i or + of the distance from snout to origin of dorsal fin . . . . 2. troscheli. 
2. Dorsal shield subcrescentic, considerably smaller than in G. troscheli. 
a. Fontanel produced posteriorly into a feeble groove which does not extend to the 
parieto-occipital ; adipose fin a little longer than the dorsal fin. 
Width of mouth 3 the width of head . . 2. . 1. ee ew ee ee 8 planiceps. 
Width of mouth 4 the width of head . 2. 2. 1. we ew ew ew ww A hessleri. 
b. Fontanel produced posteriorly into a well-developed groove which 
extends to the parieto-occipital ; adipose fin shorter than the 
dorsal fin . 2. 2. 6 ee ew ee ew eee ww ww) 5. platypogon. 
II. Teeth present on palatines and usually on the vomer, but not on the pterygoids, the 
vomerine patches separate or subcontinuous, and continuous or subcontinueus with or 
separate from the palatine patches, which may be rounded, oval, club-shaped, or oblong. 
A. Fontanel not produced backwards into a groove ; occipital process not longer than broad ; 
inner edge of pectoral spine moderately or strongly serrated; anal of 16 to 20 rays. » 
