SPAROID FISHES OF AMERICA AND EUROPE. 523 
XXVIII. DIPLODUS. 
Diplodus Ratfinesque, Indice d’Ittiologia Siciliana, 54, 1810 (annularis). 
Sargus Cuvier, Régne Animal, 1817, ed. 1, 272 (sargus; name preoccupied in Insects). 
Type: Sparus annularis Gmelin. 
Ktymology: o:zddos, double; cdodc, tooth, from the two forms of teeth. 
The name Diplodus should of course supersede Sargus, both from the 
fact that it is prior in date and because the latter name was earlier 
used for a genus of insects. The genus Diplodus, as it is here under- 
stood, differs from Archosargus chiefly in the absence of a procumbent 
dorsal spine. Most of the species of Diplodus are European, as those 
of Lagodon, Archosargus, and Stenotomus—the genera which have the 
procumbet dorsal spine are American. The skull in Diplodus resem- 
bles that of Archosargus, but the cavernous or honeycombed structure 
of the interorbital area is still more prominent. 
ANALYSIS OF AMERICAN SPECIES OF DIPLODUS. 
a. Scales, 7-56-14; depth in adult, 24 in length; black bar extending entirely across 
caudal peduncle; body regularly elliptical, moderately compressed; head, 3% 
in length; profile regularly rounded, not as steep as in argenteus; eye, 1} in 
preorbital, 14 in snout, 44 in head; mouth large, almost horizontal; maxil- 
lary, 34in head; incisors, +, inserted obliquely ; molars in three series above and 
two below; longest dorsal spine, 23 in head; caudal deeply forked; second 
anal spine little larger than third, 34 in head; ventrals reaching half way to 
the anal fin; pectorals not reaching to first anal spine; steel-blue above, paler 
below, a broad black border on the operculum; a black spot on upper part of 
base of pectoral) xr, 14 ori1b yA W132) 38a e4- eee HOLBROOKI, 124. 
aa. Scales, 8-62 to 65-16; black bar not extending entirely across caudal peduncle. 
b. Eye, 34 in head, 1 in snout; second anal spine, 2% in head; body much com- 
pressed; dorsal outline greatly elevated; depth, 1{ in length; head, 34 in 
length; profile almost straight, very steep; eye large, 14 in preorbital; mouth 
moderate, almost horizontal; maxillary, 34 in head; incisors, 4, placed as in 
holbrooki; molars as in holbrooki. Longest dorsal spine, 2} in head; caudal 
long, forked; second anal spine much stouter and 4 longer than third; ven- 
trals reaching half way to second anal ray; pectorals reaching to first anal 
spine; steel-blue above, silvery below; a blackish border on the operculum; 
a black spot on the upper part of the base of pectoraly; five or six very nar- 
row, oblique blackish crossbars; D. x11, 14; A. 111, 18; scales, 8-62-16. 
ARGENTEUS, 125. 
bb. [Eye, 44 in head, 14 in snout; second anal spine, 34 in head; depth, about 2 
in length; incisors, rather broad, implanted obliquely; three series of molars 
above, two below; eye, 14 in interorbital; crown of head convex, a protu- 
berance above the anterior angle of the orbit; preorbital not entirely covering 
maxillary; pectoral fin extending to origin of anal; ventrals nearly to vent; 
silvery or shining golden, with many narrow longitudinal dusky stripes (8 or 
9 above lateral line, 15 or 16 below), and with four or five narrow blackish 
crossbands, the first between the origin of the dorsal and the axil; D. x1 or 
xu, 12 to 15; A. 111, 13 or 14; scales, 8-65-16.] (Giinther).......SARGUS, 126. 
