of a fevT dr.ys they get henvrer ngain nnd stnrt r.tt cluing themselves 

 to the walls r.nd the bottom of the aqur.rium* T'lhile the earlier 

 stages seen to tlirive in a relatively brisk turbulence,, ivhich 

 reminds of the sucking notion of the v/nves betvreen the rocks out 

 in the sea, the 4th stage lobsters prefer- a very slov cui'rent; they 

 biiry themsf?lves under stones or shells. This jstep of the develop- 

 ment is therefore called the botton stagCo 



'to^ 



The time required for development up to the 4th stage is - as 

 shorm by my father - dependent upon the temperature of the sea 

 vfcter. At a normal sumaer temperatLire on the Skagerak coast - 

 about 16-18 degrees C« and otherT/ise favorable conditions, the 

 development takes about 14 days. 



From, now on the young lobsters lead a hidden life; they 

 practically do not appear in the aquarium in daylight. This tend- 

 ency to live r hidden life is tVie reason v/hy we do not knar; these 

 stages from naturee YJlien we liberate lobsters in the bottom stage 

 into the shoal re^"ions, it is remarkrble how quickly they hide 

 between algae and rocks. 



The young lobsters live this- hidden life b-th in the aquarium 

 -and in nxiture until- they reach 'a leiigt)i of/about seven centimeters. 

 V'Jlien they hrve reached this size, they more often ''go . for a walk," 

 esp, in tvj-ilight, and when they are Cibout 10 cm. long, -the fishermen 

 catch them \Tith their tools, osp» the hoop nets» 



I have found out thct it is best to study the lobster in nature 

 during the dark, quiet August nights. During t?ie day it is hard to 

 find the lobster because it is hidden, but dioring the night, espec- 

 ially in the summer time, it might be found in large numbers in 

 shallow vrater by means of a good light. Lately I have used an 

 electric lantern vrhich I have- lowered into the sea. ^ "'>'>ien tlie light 

 first falls on the lobster, it keeps quiet and. is not disturbed, so 

 that one might easily make observations. If the light. gets too 

 sharp, it usually starts to move, and generally towa^jrd the place 

 v;here it hides. In this v/ay one :night find t?iese caves only by 

 roxving after the lobster. One ;aight also find the caves directly, 

 as the bottom., outside is kept .clcaii from algae, etc. Very often we 

 see part, of, the clav/s or .the. antennae sticking out. 



I have also had an opportu^i'ty to see hov/ the lobsters build 

 their houses* Partly they dig them out like caves; partly they 

 gather small stones for material. ■ -But as a rule they live in crev- 

 ices or unc'er big rocks. The lobster-' s tendency to live in caves 

 continues all its life, as far as I can understand.. 



