452 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [26] 
TABLE XII.—Numerical proportion of sexes among the Ihine salmon caught semi-monthly 
between Basel and Laufenburg. 
1878. 1879. 
Of 100 salmon there Of 100 salmon there 
Number | Number are— Number | Number are— 
of of of of 
females. | males. females. | males. 
Females.| Males. Females.| Males. 
ae ee | =| | 
July 1to15........ | 97 44 68. 8 31.2 4 | 23 85. 2 14.8 
duly 16 to 31...-.-.. | 104 41 ed, 28.3 12 38 76.0 24.0 
August 1 to 15..... 78 22 78. 0 22.0 15 46 75.3 24.6 
August 16 to 31..-. 37 13 74.0 26.0 29 71 71.0 29.0 
September 1 to 15..| 52 29 64. 2 35. 8 17 37 68. 5 31.5 
September 16 to 30.) 37 42 46.8 53.25 34 41 54.7 45.3 
October 1 to 15... .| 64 33 66. 0 34.0 79 79 50. 0 50.0 
October 16 to 31. -..) 53 55 49.0 50.9 45 37 45.1 54.9 
November 1 to 30-.- 47 19 71.2 28.8 52 63 54.8 45. 2 
569 298 65.6| 34.4 311 460 59.5. 40.5 
From the above table a corresponding change will be observed in 
both years in the numerical proportion of the sexes. Till the end of 
August the female fish are in the majority ; during September the males 
gradually increase so that the numbers become almost equal, and in 
October the relative proportions are about the same. As there is noth- 
ing in the quality of the fish, in their color, length of nose, and qual- 
ity of the flesh, to point to such a late immigration in great masses; as 
the October figures show great irregularities, and as, moreover, the 
females are again more numerous in November, [ consider it probable 
that the females during the last stage of the ovarian development 
keep much quieter than the males, and are therefore not caught as 
frequently. Mr. Glaser shares this view. It is not impossible, how- 
ever, that a larger number of such males as have hitherto roamed 
about in the Central and Lower Rhine immigrate into our region at so 
late a period. 
There are instances of direct immigration of fresh fish. In 1877 and 
1879 I observed (as an entirely exceptional case, however) male fish 
which undoubtedly were late immigrants. They had the appearance of 
summer salmon; their skin showed red spots, but was not quite as 
thick and dark as that of summer salmon; the nose was short (5 to 6 
per cent.‘of the length of the body, instead of 8 to 11), the hook was 
less developed; there was a considerable quantity of intestinal fat, and 
the flesh was still red. But these fish, of which I took note during the 
period, November to January, were never (sexually) mature. (Notices 
regarding the testicles of 4 fish, among them 2 by Prof. His, 1870).* 
The weights and the degrees of. maturity, ascertained by microscopical 
observations, differed very much, and corresponded to the normal organs 
from August till the beginning of October. The question here was by 
*Mr. Glaser remembers only two cases in 19 years where he succeeded in squeez- 
ing a little semen from such late-comers, during a late spawning season. 
