to 



thr.t hrtch Itite .fi-oia the egg cm oonclufle their first period 

 with the 7th stcgeo 



The tine for the bow^ii-mini- of inoulting in the second |:;ro\jth 

 period seems, to commence sererrl vreeks enrlior, cit Hel;-^olnnd thnn 

 on the Norwegian West Cor.st, v/hich without doubt is related to the 

 tempornture conditions of the sea water. Ehrenbaum has indeed 

 obserT,'ed shc-dding r.t the be,., inning of February and the latter Vinlf 



'of 'March, but he supposes hovever that' these times are abnoriiT.l 

 and are caused by the favorable conditions of the aquarium, a view 



■ that is undoubtedly oorrocto Tho above-mentioned indi^■•idual reared 

 by lilhrcnbaum had on the other hand mrdo its first moulting in the 

 second period on 24th May and the first in the third period on 15th 

 May (S). These times mny indeed also como nearer .to normal con- 

 ditions than the first mentionedo On our "vTest Coast -I have observed 

 the first moulting a:.;iong young individuals at the begijming of Juno, 

 as a r.a;lG hov;;ever it commences' later, as mentioned bef ores 



Boyond this stage that was reached by the individual reared by 

 ' Elirenbavim, the aforesaid scientist, \vas not able to observe directly 

 the grovrt;h of the lobster at Helgoland. He is therefore dependent 

 upon calculations that have been based on compr.risons vdth individ- 

 uals' of other coasts. Ehrenbaim himself points out (3, p» 190) 

 that his calculations ar>j uncertoin indeed if they are regarded as 

 an average. I tira also inclined to believe that he has regarded 

 tVie average grov;th of the lobster -^f t he southe?rn Horth Sea somewhat 

 too great. As support for his calculations Ehrenbauia mentions among 

 others a pair of lobsters which the Scottish worker Brook kept in 

 his aquarium at Huddersfield (a city in mid-England )<, These lob- 

 sters were respectively 17o8 and 18e3 cms. long when they Vircrc put 

 ine In the coui'sc of two growth periods (approximately 1-g yeajrs) 

 they each passed through four moult ings and, thus increased in length 

 over six cms»i I belii^ve hov;ever thau from- the conditions under 

 .which these individuals were kept, one can conclude nothing on the 

 grov-iih of the lobster, neither f or t he sox'-thcrn or northern part 

 of the North Seas In an aquarium in tho interior where the renewing 

 of the salt water muse necessarily be entirely different than on the 

 coast and- v/hei;;e especially temperature conditions xouat be therefore 

 Viigher, peculiar physical conditidus occur by -.ihich Hie animrls— if 

 one also assumes that older indi-v^iduals will be less influenced 

 than younger ones— will be influenced in quite a different way than 

 if kept in water which is steadily renewodo I asswAe that the 

 growth under these circmustances is quicker than under normal con- 

 ditions and thf± tho nvimber of castings especially is increascdo 

 TOiile he sup-?oses that tlic fijiires for these mentioned individut Is 

 also are normal for t]io lobsters of lielgoland, Ehreub-^ 1:0.11 arrives at 

 the result that there the female becomes ser. ripe for the first time 

 at the age of seven years (and of r" length of approxiiirtely 24rg- cmSo)i 

 At an age --f five years the lobsteit* should have reached a size o.f 

 21 cms o • 



