FAMILY SCIENIDA: — LEIOSTOMUS. 69 
FAMILY IV. SCIENIDA:. 
No teeth on the vomer or palatines. Denticulations or spines on the opercular bones. Mouth 
not protractile. Cheeks not mailed. Scales on the bases of the vertical fins. With one 
or two dorsal fins. Teeth various. 
This family resembles the Percide in many particulars, such as the various denticulations 
or spines on the opercular pieces, the variations in the dorsal fins and the branchial rays, etc., 
but are at once distinguished by their smooth palate. Some of the genera of the preceding 
family, with smooth palates, appear to constitute a connecting link or passage from the Per- 
cide to the family now under consideration. The Scienid@ have all a peculiar aspect, and 
may in general be readily recognized by their arched snout, and by the scales which ascend 
high upon the vertical fins; they have the habits of the Perch family, and in general are 
excellent food. The species are for the most part inhabitants of the intertropical seas ; none 
are common to both continents, and a great majority of the species are American. Many of 
them make a grunting noise, which Cuvier supposes may possibly be connected with their 
complicated air-bladder. 
The species already known exceed two hundred and fifty, which have been distributed by 
Cuvier under thirty-one genera. 
GENUS LEIOSTOMUS. Cuvier. 
Anal spine feeble. Very minute denticulations on the preopercle. Teeth in the jaws even, 
and excessively small. Pharyngeals paved on their posterior border. Snout convea, 
arched. Two dorsals. 
Oss. The name of this genus was formed by Lacépéde, upon the erroneous idea of the 
total absence of teeth. Cuvier first assigned its proper characters. 
THE LAFAYETTE. 
LeEIosTOMUS OBLIQUUS. 
PLATE LX. FIG. 195. 
Mugil obliquus. Mrrcuiux, Report in part, etc., p. 16. 
Tabrus id., Little Porgee. Ip. Lit. and Phil. Soc. Vol. 1, p. 405. 
Sciena multifasciata. LesuEur, Acad. Nat. Sciences, Vol. 2, p. 255. 
Le Léiostome a épaule noire, L. humeralis. Cuv. et Vau. Hist. Poiss. Vol. 5, p. 141, pl. 110. 
Characteristics. Fourteen to eighteen transverse oblique bands over the back. A dark 
rounded spot behind the upper angle of the opercle. Length 6 to 8 inches. 
Description. Body compressed. Back gibbous, rapidly descending to the nape. Snout 
blunt. Eyes large. Nostrils double; the posterior oblique, largest. Three or four pores at 
