NATURAL HISTORY OF AMERICAN LOBSTER. 



363 



Table 14 (after Hadley). — An Estimate op the Rate of Growth of the American Lobster 

 FROM Time of Hatching to Attainment of a Length of 22^ Inches — Continued. 



Stage. 



Approximate 

 age. 



Length. 



MilH- 

 meters. 



Inches. 



Increase. 



MilH- 

 meters. 



Inches. 



Per cent. 



Approximate time 

 of molt. 



Stage pe- 

 riod. 



Sex. 



No. 

 No. 



No. 

 V-No. 



No. 

 No. 



No. 

 No. 



No. 

 No. 

 No. 

 No. 

 No. 

 No. 



No. 

 No. 

 No. 

 No. 

 No. 

 No. 



2 years ^ 

 months. 



2 years 6 

 months. 



3 years 



3 years 6 

 months. 



4 years 



4 years 6 



months. 



4 years 6 

 months. 



5 years 



6 years 5 

 months. 6 



6 years , 



8 years 4 



months. 



7 years 



10 years 4 



months. 



8 years 



12 years 4 

 months. 



9 years 



14 years 4 



months. 



10 years 



16 years 4 

 months. 



12 years 



18 years 4 



months. 



14 years 



20 years 4 



months. 



17 years 



20 years 



23 years 



26 years 



29 years 



33 years 



162. o 

 180.0 



200.0 

 222.0 



247.0 

 247.0 



275.0 

 275.0 



300.0 

 300.0 



327.0 

 327-0 



356-0 

 356-0 



4K 



6H 



IYa. 



8 



SH 



9H 



9H 



I3T^ 



14X 



August 



November. 



May 



Autunm « . 



Late spring. , 

 Autumn. . . . 



25. ( 



25- < 



28. ( 

 28. ( 



27.. 



27. i 



26. c 

 26. c 



25.1 



25. C 



26. < 



23-' 



Late summer or autumn 



Summer 



Late summer or autumn 



Summer. . 

 Autumn. 



Summer . 

 Autumn . 



Summer. . 

 Auttimn. 



Summer. . 

 Autumn. 



Summer.. 

 Autumn . 



Summer. . 

 Autumn. 



Sununer. . 

 Autumn. 



Summer. . 



do.... 



do.... 



do.... 



do..., 



.... do.... 



M. F. 

 M. F. 



M. F. 

 M. F. 



M. F. 

 M. 



M. 

 F. 



M. 

 F. 



M. 

 F. 



M. 

 F. 



M. 

 F. 



M. 

 F. 



M. 

 F. 



M. 

 F. 



M. 

 M. 

 M. 

 M. 

 M. 

 M. 



1 After the eighteenth stage it is very doubtful whether the lobster molts oftener than twice in a year. 



b It is uncertain at just what time the spring or early summer molt for female lobsters not bearing external eggs is first omitted, 

 but it is probably near this stage. 



It is shown, however, by Hadley, that the rate of growth is more rapid in the young 

 Wickford lobsters (stages i to 17), that it begins to fall at the age of about 2>2 years 

 (stage 18), becomes differentiated in the sexes in favor of the more rapid growth of the 

 male at the twenty-third stage, and continues to decrease, the stage period becoming 

 longer and longer with age, especially in the female, where the production of eggs pro- 

 ceeds at a very rapid rate. Thus, according to Hadley, the increase in the 12 -inch lob- 

 ster has dropped to 9 per cent, or about one-half that in the first 17 stages, and while both 

 sexes have molted 25 times, the male is but 7 years old, whUe the female is 10 years and 

 4 months. Thus he thinks that the female is outstripped in the race with the other sex 

 on account of the drain upon her vitality due to the periodic production of a rapidly 

 increasing egg supply, and that this accounts for the fact that so far as observed giant 

 lobsters beyond 18 or 20 iaches in length are invariably of the male sex. 



