SPAROID FISHES OF AMERICA AND EUROPE. 523 



XXVIII. DIPLODUS. 



Diplodus Rafinesque, Indice d'lttiologia Siiiliana, 54, 1810 (annularis). 



Sai'gus Cuvier, Regue Aiiimal, 1817, ed. 1, 272 {sargitu; name preoccupied iu lusects). 



Type: Spams annular i s Gmelin. 



Etymology: 'JcttA^Wjc, double; oduuq, tooth, from the two forms of teetli. 



The mame Diplodus should of course supersede Sargiis, both from the 

 fact that it is prior iu 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 Steuotomus — the genera which have the 

 procumbent 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 t)IPLODUS. 



a. Scales, 7-56-14; depth in adult, 21 iu 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, If in 

 preorbital, 1| iu suout, 4^ iu head; mouth large, almost horizontal; maxil- 

 lary, 3^ in head ; incisors, |, inserted obliquely ; molars iu three series above and 

 two below; longest dorsal spiue, 2| iu head; caudal deeply forked; second 

 anal spine little larger than third, 3.V in head ; ventrals reaching half way to 

 the anal tin ; 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 ; D. xii, 14 or 15 ; A. iii, 13 Holbrooki, 124. 



aa. Scales, 8-62 to 65-16; black bar not extending entirely across caudal peduncle. 

 i. Eye, 3^ in head, 1 in snout; second anal spiue, 2| in head; body much com- 

 pressed; dorsal outline greatly elevated; depth, 1| iu length; head, 3^ iu 

 length ; profile almost straight, very steei> ; eye large, IJ in preorbital ; mouth 

 moderate, almost horizontal; maxillary, 3| in head; incisors, ^, placed as in 

 holbrooki; molars as in holbrooki. Longest dorsal spine, 2A iu head; caudal 

 long, forked; second anal spiue uuxch stouter and ]^ longer than third; ven- 

 trals reaching half way to second anal ray; pectorals reaching to first aual 

 spine; steel-blue above, silvery below; a blackish border on the operculum; 

 a black spot on the ujiper part of the base of pectorals; five or six very nar- 

 row, oblique blackish crossbars; D. xii, 14; A. iii, 13; scales, 8-62-16. 



Argenteus, 125. 

 bb. [Eye, 4^ in head, IJ in snout; second anal spine, oi in head; depth, about 2 

 in length ; incisors, rather broad, implanted obliquely ; three series of molars 

 above, two below; eye, 11 in interorbital; crown of head convex, a jtrotu- 

 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. xi or 

 XII, 12 to 15; A. Ill, 13 or 14; scales, 8-65-16.] {Giinther) Sargus, 126. 



