92 



Part III — Twenty-third Annual Report 









Size (inches) of 











Size 

 (inches) 

 before 



Soft Lobsters. 



Immediate 



Length 

 of Time 

 in 



JSo. 



Tilt J.1 



Month . 



Measured 



Measured 



Increase 

 in Size. 







Casting. 



just after 



f\fi pr- on 



cti. t- VZ/A < w 1 



Captivity. 









the Cast. 



Interval. 

















Inch: 





I 



J nly. 



1 O 7 



12g 



12g 



13 



0 



1 Year. 



o 





1 O 1 



12| 





1 



4 



55 



3 





10§ 



10| 





4 



5? 



4 



55 



12| 



13 





1 



4 



2 Years. 



5 



»> 



1 1 



1 1 1 





1 



4 



55 



n 

 D 



J5 



111 



ll| 





i 



1 Year. 



7 



» 



1 L 8 



ll| 





3 





g 





12 



121 





8 

 1 

 2 



}■> 

 »> 



9 



Sept, 



11 



"I 





5 



8 



55 



10 



55 



9| 







1 month. 



11 



Oct. 



ll| 

 10§ 



12 



1 



4 



1 Year. 



12 



55 



HA 





5 



1 6 



2 months. 



13 



55 



Hi 



iii 





1 



4 



2 „ 



14 



Nov. 



li 



n 





0 



3 „ 



These figures indicate that there was no great increase in size just after 

 the cast, whatever may happen during the time that the shell is harden- 

 ing. Herrick found that the lobster grew considerably during that time. 

 While most of the lobsters mentioned in the Table had been in captivity 

 for a year or more, there are four cases in which the length of confine- 

 ment was only that of a month or two. In the case of one lobster, 

 the increase in size nine months after the moult was one inch. 

 In the other short-period cases the increase was just as small 

 as with the lobsters which had been over a year in the Laboratory. 

 In two cases, in fact, the soft lobster was, as far as could be 

 ascertained, exactly the same size as the hard lobster. It was not 

 possible to separate all the soft lobsters and measure them subsequently 

 to see what increase took place during the hardening of the 

 shell. In the case of the first two lobsters, which were re-measured, after 

 intervals of two and one week respectively, an increase of ^ inch in each 

 case took place. Ehrenbaum agreed with the earlier observations of 

 Herrick and Rathbun in noting the slowness in the growth of the older 

 lobsters. He instances a case where a lobster, measuring 402cm. (16 

 inches) in length, only increased its length by a millimetre ( ^U- inch) on 

 casting. Vitzou gives measurements to show the increase that takes 

 place in different parts of the body after casting ; he demonstrated the 

 fact that while the carapace and abdomen increased in size at once, the 

 large claws only showed a marked increase 17 hours after the moult. 



Salter describes in detail the operation of casting. The lobster cast in 

 July. Immediately after it had got rid of its shell it concealed itself 

 among a mass of seaweed that it had before casting collected in a corner 

 of the tank. Brook observed that a male lobster buried some food 

 before casting, and after another cast it partially buried its cast integu- 

 ment in the sand. 



