= 
158 THE AMERICAN MIDLAND NATURALIST. 
search vessels, in order to ascertain to what extent ‘seasonal 
variations occurred in the proportions of males and females 
caught in various parts of the North Sea. The total number 
of plaice studied was 179,118; of these, 89,945 were males 
and 89,173 were females. The percentages in the different 
length-groups (5-cm. increment) ranged from 55% males, 
45% females, for the youngest fish, to 8% males, 92% fe- 
males, for the oldest fish. WALLACE (1914, p. 79) showed for 
different areas that while for the average populations investi- 
gated in different areas of the North Sea during the year 
1906-1909 the males were usually almost as abundant as the 
females (ca. 45% males), nevertheless, after the sixth, and 
particularly, the seventh, year of life, practically all the indi- 
viduals were females (ca. 80%-100% females.) 
b.) THE CANADIAN PLAICE, Hippoglossoides platessoides 
Fabr. 
HUNTSMAN (1918) finds evidence to show in this fish that 
for the first two or three years of life there are more males 
than females, but that the older the fish become, the smaller is 
the relative numer of males, until finally, females alone are 
found among the oldest fish. In the Gulf of St. Lawrence, 
where there are fish of many different ages, he found the 
males more numerous than the females among the three-year- 
olds, but for the later years fewer and fewer males, until 
finally after an age of 14-24 years (with the single exception 
of the 21-year-old group) only females were found. He con- 
cludes that “there must surely be a higher death-rate among 
the females in early life, and among the males later, and this 
is not influenced by the temperature, as similar proportions 
of the two sexes for the various years of life are found both 
where there is rapid growth and early maturity in warm 
water, and also where there is slow growth and late maturity 
in cold water.” 
c). THE WITCH, Pleuronectes cynoglossus L. 
FULTON (1904), p. 195) has called attention to the abun- 
dance of males among populations of young witches, while 
among the older populations the proportions were reversed. 
