9 
methyl orange was used as an indicator, was probably acid to phen- 
olphthalein. 
Wells shows that fresh-water fishes recognize and react to the 
presence of salts in solution, the reaction being such as will bring 
them into their optimum salt concentration. From his own and 
from Shelford’s work on the salt-water fishes, Wells concludes that 
fresh water and probably salt water fishes are not so sensitive to 
salt ions as they are to hydrogen and hydroxyl ions. He also shows 
that starvation causes some fishes to select higher concentrations of 
salts than those normally selected, while the reverse is true of other 
species of fish. 
toule (9) believes that salmon migrate to a richer supply of 
oxygen. 
Lirz History or FunpuLus Hrrrrociirus 
Fundulus heteroclitus is “the killifish of Schopff, the yellow- 
bellied and the white bellied killifish of Mitchill and the big killifish 
and barred killifish of De Kay. ‘he Indian name ‘mummichog’ is 
apphed to this as well as other species and some persons call it the 
salt water minnow. It is also called the mud-fish, cobbler and pike 
minnow.” [Bean (1) — 
The killifishes are characterized by banded markings, rounded 
fins, a very convex tail fin, short head, obtuse snout, space between 
the eyes very flat, lower jaw projecting, and a length of not more 
than 6 or 7 inches. 
The male reaches a length of about 5 inches and is easily dis- 
tinguished at all ages and in all seasons by the presence of a number 
of transversely arranged silver bars on the sides and a yellow or 
orange colored belly. ‘The ground work of the body is dark green, 
and in mature specimens at the breeding season there are numerous 
white and pale yellow spots of color on the sides. ‘The dorsal fin 
of the male bears a dark spot at the base of the last rays; in the young 
male this dark spot is subdivided into two blotches. The vas deferens 
extends to the anal fin or even a little way along the anterior ray. 
The young female has dark bands like the silver bands of the 
male, and during the spawning season some older females show the 
dark bands against their olive ground color. The majority of the 
older females, however, rarely show the transverse bands. ‘The ovi- 
duct extends along the anterior ray of the anal fin about two-thirds 
its distance. 
It is interesting to note that the killifishes have the power of 
changing their color rapidly to agree with their background. ‘This 
serves them well in escaping the notice of some of their enemies, 
as well as enabling them more readily to approach their living food. 
In New Jersey in the vicinity of New Brunswick, the spring 
migration begins as early as the latter part of March and gravid 
females were found as early as April 19, 1915. The spawning season 
