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BULLETIN OF THE BUREAU OP FISHERIES 
of development due to differences in temperature, but that it may be said to be 
from 8 to 27 days. Concerning the smelt of the Elbe, Ehrenbaum (1894) says that 
four to five weeks are necessary. 
In one of Mather’s experiments (1885) it seems that the eggs began to hatch 
in 36 days, the temperature of the water ranging from 40° to 42° F. In another 
they hatched in 30 days with the temperature at 37° to 58° F. At five days old 
the formation of the embryo was visible by means of a microscope, and in 15 days 
the embryo could be seen with the naked eye. In another they also hatched in 30 
days with temperature ranging from 40° to 65° F. 
Concerning the smelt of Finland Reuter (1883) stated that the roe is developed 
in about three weeks. 
In 1909, Race wrote that the incubation period of the “large” form of the 
fresh-water smelt at Green Lake, Me., was 30 days with a range of temperature 
from 33° to 34° F. The period of the “small” smelt was 24 days with the temper- 
ature ranging from 45° to 48° F. 
In his report for the fiscal year ended June 30, 1922, Superintendent John A. 
Story of the Green Lake (Me.) station of the Bureau of Fisheries wrote: 
The advance run of smelts was very favorable. On April 26 many smelts were in the brook 
and 40 quarts were caught. More could have been caught, but on careful examination it was 
found that nearly all were males, there being about 25 males to one female, and it was decided 
that the next night would be the proper time to take them, as more females would then be in the 
brook. That night a cold rain set in, continuing all next day, which drove all the smelts back to 
the lake and practically no smelts came back into the brook. Other brooks were visited, but 
very few smelt eggs were obtained from the smelts caught April 26. These were left to hatch in 
the trough in which they were deposited. The dam board at the foot of the trough was removed 
to make quick water over the eggs and allow the fry to run out as fast as hatched. These eggs 
hatched in 18 days with practically no loss, the temperature registering 51.55° F. 
In the report of the same station for 1924 Mr. DeRocher stated that in the 
case of the large smelt “eye spots” appeared in 20 days. 
DEVELOPMENT 
According to Cunningham (1896) the newly hatched larva is 5.5 to 6 millimeters 
long (0.24 inch, or less). The mouth is already open, but beneath the head; the 
yolk is much reduced, and the oil globules all united into one, which is situated near 
the front end of the yolk sac. The primitive fin membrane is narrow; the intestine 
ends near the end of the tail, far behind the yolk sac, as in the larvae of the herring 
family. The pigment is very scanty; there is some in the eyes and specks on the 
yolk sac and along the lower edge of the body. The whole larva is delicate and 
transparent. 
The present writer’s observations upon the American Atlantic smelt, which 
have been in comparatively small brooks, indicated that the tiny transparent young 
do not remain long in the place of their birth. Probably, because the eggs are more > 
or less suspended above the bottom, the current of the water takes the majority of 
young smelts downstream almost as soon as they are hatched, thereby being sub- 
jected to all sorts of vicissitudes, and comparatively few survive to attain the adult 
age. It is a provision of nature to offset such contingencies that the smelt is so 
