FISHES OF CHESAPEAKE BAY 191 
ber of scales in a lateral series, as well as the number in advance of the dorsal, appear to be quite 
distinct in the two species. 
The food of this fish, as indicated by the contents of 20 stomachs, consists of the following, 
named in the order of their apparent importance: Small crustaceans, small mollusks, insects, and 
worms. A few strands of algae also were found. 
The spawning season of this fish is a protracted one, as ripe or nearly ripe fish were taken 
from April 10 to September 19, 1921. It is also quite probable that the fish spawns more than once 
during a season, since the female, for example, has ova of several sizes in the ovaries at one time; 
and when one lot of eggs is ripe those of the next largest size are big enough to be plainly visible 
to the unaided eye. The eggs, when spawned (Hildebrand, 1922, p. 120), are not quite spherical, 
and they are somewhat smaller than those of M. menidia, their greatest diameter being approxi- 
mately 0.75 millimeters. The eggs, as in M. menidia, are provided with gelatinous threads, which 
in the present species are comparatively few in number, and one of them is always much enlarged. 
The eggs adhere to objects in the water by means of these adhesive threads. Hatching took place 
in 8 to 10 days in water varying from 78° to 82° F. The newly hatched larvae are approximately 
3.5 millimeters in length, very slender, and highly transparent. 
The females appear to grow somewhat larger than the males. The maximum size, according 
to Chesapeake specimens, is 75 millimeters (about 3 inches) for the female and 70 millimeters 
(2% inches) for the male. The fish is abundant in the bay and it is found in association with M. 
menidia, being more fresh-water in its habits, however. It is more common in brackish than in 
salt water, and it ascends streams into strictly fresh water, the species having first been discovered 
in the Potomac River at Washington. It was not taken in deep water at beam-trawl stations. 
Because of its small size this silverside is of no direct commercial importance; its chief value is as 
food for larger predatory fish. 
Habitat . — Cape Cod, Mass., to South Carolina, entering streams and fresh water. 
Chesapeake localities. — (a) Previous records: Baltimore, Washington, Alexandria, Bryans 
Point, lower Potomac, Hampton, and Cape Charles city. (6) Specimens in collection : From many 
points from Havre de Grace, Md., to Cape Charles and Lynnhaven Roads, Va. 
72. Genus MEMBRAS Bonaparte. Rough silversides 
Margins of scales strongly lacinate; base of dorsal and anal with a sheath of large deciduous 
scales. The genus probably contains only two species, one from Martinique and one from the 
Atlantic and Gulf coasts of the United States. 
95. Membras vagrans (Goode and Bean). Silverside; Sardine; Silverfish. 
Chirostoma vagrans Goode and Bean, Proc., U. S. Nat. Mus., 1879, p. 148; Pensacola, Fla. 
Kirtlaniia vagrans Jordan and Evermann, 1896-1900, pp. 794 and 2840, PI. CXXIV, fig. 336; Evermann and Hildebrand, 
1910, p. 160. 
Head 4 to 5.9; depth 4.9 to 6.7; D. IV to VI-I, 6 to 8; A. I., 17 to 22 (usual formula I, 18 to 
21); scales 42 to 49. Body elongate, moderately compressed; caudal peduncle rather strongly 
compressed, its depth 1.1 to 1.4 in head; head rather flat above, narrower below; snout pointed, 
2.85 to 3.15 in head; eye 2.5 to 3.55; interorbital 2.45 to 2.9; mouth small, oblique, strongly pro- 
tractile; lower jaw included; teeth in the jaws small, pointed, in narrow bands, the outer series of 
teeth somewhat enlarged; scales firm, lacinate, distinctly rough to the touch in adults, the lacina- 
tions not evident in young of less than 30 millimeters; scales extending on the base of vertical 
fins; origin of spinous dorsal usually over origin of anal, about equidistant from posterior margin 
of opercle and base of caudal; soft dorsal placed over posterior part of anal base, the two fins being 
nearly coterminal; caudal fin moderately forked; anal fin rather long, its origin about equidistant 
from margin of opercle and base of caudal; ventral fins rather small, inserted about equidistant 
from tip of snout and base of caudal; pectoral fins pointed, the upper rays longest, 1.1 to 1.4 in head. 
Color greenish on back, silvery on lower parts of side and belly; sides with a broad silvery band, 
bounded above by a dark line, width of band equal to about three-fourths diameter of eye; scales 
on the back with numerous dusky points; occipital region and tip of snout often bluish or dusky; 
caudal fin more or less dusky, yellowish in life; other fins mostly plain; peritoneum silvery with 
dusky punctulations. 
49826 — 28- 
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