NATURAL HISTORY OF AMERICAN LOBSTER. 365 



I think it highly probable now, as I did in 1 892-1 894, that lobsters grow more rapidly 

 in nature than when confined in glass jars in a hatchery, but that the measurements of 

 the early stages of the lobster which were then made were correct for the place and time 

 there can be no doubt. They were taken upon a standardized scale, and made with 

 care under a hand lens or dissecting microscope. 



The lobster in the first stage, according to our table, was found in fifteen measured 

 individuals taken from the hatching jars to have an average length of 7.84 millimeters 

 (extremes 7.50 to 8.03 mm.), against an average length of 8.2 millimeters as given by 

 Hadley for Wickford, R. I. The eggs from which these young were hatched at Woods 

 Hole were stripped from old lobsters, taken in June to July, and placed in the McDonald 

 type of jar then in use. The mean average temperature of the sea water at the U. S. 

 Fish Commission wharf for a period of five years from 1889 to 1893 was for June 62.1° F., 

 and for July 69.1° F. The water in the hatching jars was found to average one degree 

 higher than that outside. Since I could not begin operations until the latter part of June, 

 the eggs with which I had to deal directly or indirectly had reached a late stage of devel- 

 opment under natural conditions, and were near the hatching point when taken. Ac- 

 cordingly these eggs were probably not undersized and the larvae may be regarded as 

 normal for Woods Hole for the period in question. 



What is the average length of first-stage lobsters hatched in the waters of Vineyard 

 Sound? Although during six consecutive seasons (i 889-1 894) I never succeeded in 

 taking, with the net at the surface of the sea, under natural conditions, a single larva 

 of the first stage, and but one of the third stage, this question can be partially answered 

 by the earlier observations of Smith (256) m^de in 1871, who says that "the lobsters in 

 the first stage were first taken July i , when they were seen swimming rapidly about at the 

 surface of the water among great numbers of zoeae, megalops, and copepods." * * * 

 "They were frequently taken at the surface in different parts of Vineyard Sound from 

 the 1st to the 7th of July, and several were taken off Newport, R. I., as late as 

 July 15, and they would very likely be found also in June, judging from the stage of 

 development to which the embryos had advanced early in May in Long Island Sound. 

 These young lobsters with two exceptions were taken at the surface in the daytime 

 (forenoon) from July i onward, but not so commonly as young in the fourth stage." 

 Smith gives the measurement of the first stage as 7.8 to 8 millimeters. It therefore 

 seems probable that the average length of Woods Hole lobsters in the first stage is under 

 8 millimeters, and not above this measure as found by Hadley for the same stage at 

 Wickford, but probably above 7.84, the average found for the artificially hatched young. 

 If this be the case, it is quite certain that the rate of growth up to at least the tenth 

 stage is slower than at Wickford, as is further indicated by the longer stage periods. 



Hadley concluded that a 11 -inch male lobster from Wickford was 6 years old, while 

 a female of the same length was 8 years of age, whereas upon the Massachusetts coast 

 this length is not attained in less than 7 and 9 years, respectively. Accordingly a lo-inch 

 Wickford male would* be about 6 years old, and a female of the same length somewhat 

 over 7 years. I am inclined to doubt whether the difference is really as great as is here 

 implied. 



