136 
BULLETIN OF THE BUREAU OF FISHERIES 
The food probably consists largely of vegetable matter. In 20 stomachs examined, only sand, 
mud, d6bris, and filamentous alga were found. The intestine is convoluted and more than twice 
as long as the body, which is a further indication that the species is chiefly herbaceous. In the 
aquarium this fish readily feeds on fish and other meats. It is very ferocious in confinement, 
waging constant fights with other fishes. Whether they are of its own kind or of another species 
does not appear to make a particle of difference. It frequently kills fishes larger than itself by 
making repeated attacks and inflicting wounds here and there with its sharp tricuspid teeth until 
the victim succumbs from exhaustion or from the attack of disease. It then proceeds to devour 
its prey by tearing off piece after piece at any convenient place. 
Spawning takes place throughout the spring and summer (Hildebrand, 1917, p. 13), one female 
laying eggs several times during one season. The eggs are spherical and about 1.2 to 1.4 milli- 
meters in diameter (Kuntz, 1916, pp. 410-414). They are slightly heavier than sea water and 
adherent, being held together by minute adhesive threads. The period of incubation at ordinary 
summer temperatures in the laboratory extended over five to six days. The newly hatched larva 
is quite plump and about 4 millimeters in length. At a length of 9 millimeters the young fish 
already has many of the characters of the adult, and at a length of 12 millimeters virtually all of the 
diagnostic characters of the full-grown fish are developed. 
The males of this species, contrary to the more usual rule among fishes, especially in related 
genera, are notably larger than the females, the average difference in length being about 12 milli- 
meters. The sexual differentiation in color takes place when the fish are about 30 millimeters long. 
The young of 8 millimeters and less in length are almost entirely unmarked, but when the fish 
becomes a little larger, spots and bars appear and all the young (males and females) assume the 
color of the female. 
This minnow is very common in all brackish waters of Chesapeake Bay, from Cape Henry to 
Love Point and Annapolis, but none at all were found from Baltimore to Havre de Grace, and none 
were taken in strictly fresh water. It is especially abundant in coves, bays, ponds, and creeks, 
and less common along the open beaches. In one instance, while collecting near Buckroe Beach, 
one haul with a 30-foot bag seine yielded about 1 bushel of variegated minnows. This minnow 
generally travels in schools, and on a rising tide swims about near the shore’s edge in water 1 or 2 
inches deep. At high tide the fish work their way up among the grass on overflowed banks, returning 
to open water with the receding tide. 
The largest specimen taken during the investigation was 76 millimeters (3 inches) long, and it 
represents the maximum size attained by this species. It is too small to be of commercial impor- 
tance, but on account of its abundance and wide distribution no doubt it is an important food for 
larger fishes. 
Habitat . — Coastwise in brackish water from Cape Cod, Mass., to Mexico. 
Chesapeake localities. — (a) Previously recorded from “Chesapeake Bay,” “Lower Potomac,” 
St. George Island, Tolchester, and Chestertown. (6) Specimens in collection: From many parts of 
the bay, from Love Point, Md., to Lynnhaven Roads, Va. 
45. Genus LUCANIA Girard. Rain-water fishes 
Body rather short, compressed; head small; mouth small, nearly terminal; teeth in the jaws 
pointed, in a single irregular series; scales rather large; dorsal and anal fins rather small, the dorsal 
above or in advance of the anal; the anal fin not modified; oviparous. A single species occurs in 
the waters of the Chesapeake. 
58. Lucania parva (Baird and Girard). Rain-water fish. 
Cyprinodon parvus Baird and Girard, Ninth Smithsonian Report, 1854 (1855), p. 345; Greenport, L. I. 
Lucania parva Smith, 1892, p. 68; Jordan and Evermann, 1896-1900, p. 665, Pi. CIX, fig. 292; Evermann and Hildebrand, 
1910, p. 159. 
Head 3.4 to 3.7; depth 3 to 3.8; D. 11 or 12; A. 10 or 11; scales 25 or 26. Body rather short, 
compressed; caudal peduncle rather strongly compressed, its depth 1.6 to 2.4 in head; head small, 
about as deep as broad at eyes; snout blunt, its length 3.5 to 6 in head; eye 3 to 4; interorbital 1.3 
to 1.8; mouth nearly terminal, the lower jaw projecting slightly; premaxillaries protractile; teeth 
small, pointed, in a single irregular series in each jaw; scales rather large, 6 or 7 oblique series between 
