THE AMERICAN LOBSTER. 



73 



It should be borne in mind that, as we have already seen, a certain number of 

 lobsters from 9 to 12 inches long have never borne eggs. Thus the chances for error 

 in making estimates of this kind are further increased. 



The percentages given in table 21 must therefore be greatly increased to express 

 the ratio between the actual spawners of the current year and those which have 

 reached the spawning age, since in the total number of females there were undoubtedly 

 included many which were not mature. While the percentage of egg lobsters taken 

 in the same locality may vary considerably from year to year or from month to month 

 it seems probable that if we could average the results taken from many different 

 localities along the coast we should find that the number of spawners each year 

 represents about half the total number of mature females. 



RELATIVE ABUNDANCE OF THE SEXES. 



Some species of Crustacea are strictly monogamous, such as the beautiful tropical 

 shrimp, Stenopus hispidics, which is always seen swimming in pairs, the male and 

 female being rarely separated. This is also true of another delicate shrimp, Pontonia 

 domestica, which lives in the mantle chamber of the mollusk Pinna. In such cases the 

 sexes are of necessity about equally divided. But in the lobster there seems to be 

 no attachment of this kind. It is probable that a given male fecundates more than 

 one female, and it is certain that the sexes are distributed with great irregularity, at 

 certain seasons of the year at least, as I shall presently show. ^Nevertheless, if an 

 extended census could be taken, at different points on the coast, it is very probable 

 that but little difference would be found in the numbers of the sexes. 



The following table shows the relative abundance of male and female lobsters 

 found in Woods Hole Harbor and at JSTo Man's Land: 



Table 22. — Relative abundance of male and female lobsters at Woods Hole and Xo Man's Land 



Date. 



Total 

 catch. 



Woods Hole : 



188!). Ayril 24-30 '• 104 



May ! 942 



June ' 2, 184 



189:!. December 224 



1894. January | 501 



February I 246 



March 348 



April I 457 



May -. 434 



June 447 



Totals j 5, 887 



No Man's Land: 



1894. May ' 1,318 



49 

 440 

 ,009 

 123 

 250 

 116 

 161 

 247 

 197 

 219 



2, 811 



Female. 



84 



55 

 502 

 1,175 

 101 

 251 

 130 

 187 

 210 

 237 

 228 



Per cent 

 of females 

 to males. 



112.2 

 114. 3 

 116.6 



82.1 

 100.4 

 112.07 

 116. 15 



85. 02 

 120. 30 

 104.11 



3,076 



106. 30 



1,234 1,469 



In the monthly catches at Woods Hole in 1889 the females preponderated by 12 to 

 10 per cent, while in the total catch for 1893-1891 the sexes are very nearly evenly 

 divided. During this period the percentage of females to males fluctuated from 82.1 

 minus to 120.30 plus, a variation of about 38 per cent. The traps were stationary, 

 but the lobsters were constantly moving about over the bottom; yet there was no 

 segregation of the sexes, and such variation as we find in the monthly catches has tio 

 special significance. 



