50 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
NUMBER OF EGGS LAID AND THE LAW OF PRODUCTION. 
The production of ova among animals is directly correlated with the condition of 
the young at the time of hatching. Where eggs are very small and present in large 
numbers, as in some of the crabs, we may look for a long larval period; when the ova 
attain a much greater size and are at the same time very abundant, as in the lobster, 
we find the larval period abbreviated; in other cases, as in some shrimps, where eggs 
are relatively very large and few, the young hatch with the external characteristics of 
the adult. 
The production of a large number of eggs always means great destruction under 
natural conditions. In such cases, however, the opportunity is afforded of increasing 
the supply of adults, provided we are able to tide the larvae over their earlier stages 
of development. The number of eggs produced by the lobster is thus a subject which 
deserves careful attention in view of its economic bearings alone. 
The numbers here recorded are based upon the records kept at the United States 
Fish Commission station. The eggs of each individual were carefully removed from 
the “tail” of the female lobster and measured in a graduate (having sloping sides), 
and the whole number of ova was estimated on the basis of the number contained in a 
fluid ounce. Mr. Edwards found the number of new eggs in one fluid ounce to be about 
6,440 (in one ounce 6,461, in another 6,419), and the number of old or well developed 
eggs in an ounce to be 6,090. This is a relatively rough method of determination, and 
the results are of course only approximately accurate. 
I estimated by weight the number of fresh eggs carried by a lobster 13 inches long 
to be 17,623; total weight of eggs, 54.9 grams; number of living eggs to the gram, 321. 
These eggs were in an early stage of development. 
The number of eggs borne by a large and a small lobster, carefully determined 
both by the wet and dry methods by my assistant, Mr. F. C. Waite, is given in the 
following table: 
Table 14. — The production of eggs determined by different methods. 
Observations. 
Lobster No. 51, 
table 20 ; from 
Gay Head. 
Lobster No. 69, 
table 20 ; from 
Woods Hole 
Harbor. 
Late segmen- 
tation . 
15J 
815 
1. 2255 
68. 8092 
220 
6, 248 
56, 079 
56, 148 
58, 500 
Post-nauplius ; 
about three 
weeks old. 
Or 
1, 009' 
0. 9893 
10. 4029 
211 
5, 992 
10, 507 
1(1, 514 
10,919 
Number of eggs determined by the dry method (a ) . 
Number of eggs determined by the dry method (b ) . 
Number of eggs determined by the wet method (c) . 
Mr. Waite estimated the number of eggs in a fluid ounce (on the basis of 2,110 
to 10 c.c., the number obtained by count) to be 5,992. These eggs had been in strong 
alcohol for upwards of three years. They were about three weeks old when preserved, 
and in alcohol had an average diameter of 1.625 mm. (1.56, 1.69 mm.) 
In the wet method ( c ) employed, the number of eggs was estimated upon the 
actual number, obtained by counting, in 10 c. c. In the dry method the number was 
