FISHES OF CHESAPEAKE BAY 225 
bearing filaments in young; soft dorsal and anal elevated anteriorly, some of the rays much produced 
in adult. 
119. Selene vomer (Linnaeus). Moonfish; Lookdown; Horsehead. 
Zeus vomer Linnseus, Syst. Nat., ed. X, 1758, p. 266; America. 
Argyreiosus vomer Uhler and Lugger, 1876, ed. I, p. 112; ed. II, p. 94. 
Selene vomer Bean, 1891, p. 87; Jordan and Evermann, 1896-1900, p. 936, PI. CXLIV, fig. 393, and PL CXLY, fig. 393a. 
Head 2.15 to 2.4; depth 1.15 to 1.3; D. VIII-I, 21 or 22; A. II-I, 18 or 19. Body ovate, very 
strongly compressed, the outlines trenchant; back much elevated; anterior profile steep, oblique, 
nearly straight, forming an angle with dorsal outline; head short, very deep; snout moderately 
projecting, 1.55 to 1.9 in head; eye 4 to 5.85; interorbital 4.2 to 5.45; mouth moderate, oblique, 
slightly superior; maxillary broad, 2.7 to 3.4 in head; teeth small, present on jaws, vomer, and 
tongue; gill rakers slender, about two-thirds length of eye, 24 or 25 on lower limb of first arch; 
lateral line with a prominent arch anteriorly, equal to or a little shorter than straight part, without 
developed bony scutes posteriorly; first dorsal with eight spines, the anterior ones slender, bearing 
Fig. 131.— Scheme vomer 
long filaments in young; second dorsal and anal similar, the anterior rays much produced; caudal 
deeply forked; ventral fins very long in young, often reaching to or beyond base of caudal, very 
short in adult, about equal to length of eye in specimens 200 millimeters in length; pectoral fins 
long and falcate in adult, moderate in young, 2.05 to 3.25 in length of body. 
Color in life of a specimen 175 millimeters long, bluish green, shading into bright silvery on 
sides; spinous and soft dorsals plain, the produced rays dusky; caudal yellowish, the lobes slightly 
dusky; produced rays of anal dusky white, anterior short rays yellowish, rest of fin plain; ventrals 
dusky brown; pectorals plain. A fish 144 millimeters long differed from the preceding as follows: 
Spinous dorsal dusky; no dusky markings on caudal; produced rays of anal dusky yellow. Young 
90 millimeters long with a dusky yellow bar from spinous dorsal through eye, followed by four or 
five less distinct yellow bars; produced rays of dorsal black, anterior shorter rays dusky yellow, 
posterior rays plain; caudal tinged with yellow; produced rays of anal dusky yellow; ventrals 
black; pectorals plain. 
This fish is represented in the present collection by 21 specimens, ranging in length from 60 to 
235 millimeters ( 2 % to 9M inches). The moonfish is recognized by the very deep body, straight 
