the lobster is also subjected during the Ir.rval s tages to such 

 variations which hr.ve their basis in the individual itself and 

 not on external influences* 



ITe left the sxiiall lobster in its entrance into the fo\irth 

 stf^.ge vdii'ch neans after it had completed all larval stages* In 

 reference to the dviration of the fourth stage, it is nore difficult 

 to specifj'- definite figures since nov; a bi '^ger difference becones 

 . evident. The shortest stage that I oould ascertain amounted to 

 about 15 days; it i;r.y hov/ever com:;ionly take 20 days on our rfest 

 Coast. In an er>rlier publication (3) I specified tv/o definite 

 periods, namely 23 and 28 days for this stage, on the basis of 

 observations that I made on two individuals reared in the Biological 

 Station at Bergen. Here it must hox/over be noted that it concerned 

 abnormally late hatched larvae (end .of August) which therefore 

 spent their first grovrth period unifer less suitable ex"l;ernal condit- 

 ions v>rhich moans at a lovrer than usua.l iiuan temperatures I believe 

 therefore that an average period of 20 days would thus fairly comply 

 with the average conditions e At the age of 45-50 days, thus about 

 after six weeks the fifth stage may be reached on o ur West Coast© 

 Under especially suitable temperature conditions --it must be 

 mentioned~the period can be much shorter. 



In the following stages the variations become alvrays bigger and 

 the moultings more irregular and more difficult to follow so that I 

 cannot give averages vrith certaintyo Both the above named individ- 

 uals of the Bergen Biological Station shov/ed in this respect very 

 little agreement since the fifth stage lasted five vrceks for the 

 one and eight weeks for the other in spite of the fact tha.t they 

 vrere hatched at the same time, had made their previous moulting at 

 approximately the same time and vrere kept in the same glass aquariim. 

 l/ TTe will therefore not dwell longer on this in order to determine 



l/ I will here give the various times at which the above named 

 small lobsters j.ioulted into the later stages. For one 

 .indivic?ual it xrr.s o3fi the 17th September (4th stage), on 10th 

 October (5th stage), 16th Nove:nber (6th stage); v;ith this 

 the first grovrth period v/as terminated. The second specimen 

 moulted on 19th Septei.iber (4th stage), 17th October (5th 

 stage), 18th December (6th stage). 



the duration of the various stages in the first year of life, bub 

 deal v/ith more general questions that are closely related to the 

 above statements : liovj; mniiy ■ aoultings ;\oes a lobster lar va ;.iake_ 

 during the first growth period -and vjhat size does it reach at the 

 s ame time? " ' 



For the first question one must first of all bring into consider- 

 ation the time at v^hich the larvae hatched. A larva hatched early 

 in the summer, for example, in the iriiddle or end of July, can pass 



