observed by ne in the floating boxes was seven days \Thile the 

 average here amounts to 10-11 days. V Seven days v/as the minimum 



\J For the experiments in 1908 the shortest tine for the first 

 and second stages was nine days at a mean temperature of 

 approximately 16° C. 



duration of the third stage, the average must be regarded as 10-12 

 days. Thus \7e see that the lobster larvae on cour West Coast need 

 approximately 26-30 days, or four vreeks , to pass completely through 

 the lairwal stages and to reach the bottom stage. 



According to this vre find for each of the first tliree stages 

 or larval stages the folloiTing age. First stage: a mnimum of 4-5, 

 average 6-7 (8) days, second stage: minimum 11-12, average 16-17 

 (19) days and third stage: minimum 18, average 26-29 days. These 

 figures are slightly higher than those vAiich Dannevig (1885) found 

 in his experiments at Fl^j^devigen which without doubt is to be attri- 

 buted" to a lov/er m.ean temperature prevailing on our West Coast. 

 ViTith especially favorable sea v/ater temperature however the develop- 

 ment on oui" West Coast can also take place somewhat more quickly. 



It is therefore clearly seen that temperature exerts a great 

 influence on the period of development this is hindered by a lcn,-;er 

 temperature and increased by a higher oneo I intended nov; to dis- 

 cover what influence it \70uld have on the development of the larvae 

 if the der^relopnent took place not in the vrarmer v/ater layers of the 

 surface but in a feiT metres of depth. I constructed therefore in 

 1899 a box of exactly the same construction as the others used as 

 breeding boxes in the surfacej it was hovrever fitted with a cover 

 of the same kind of net that vms used on the sides c This box was 

 then sunk to a depth of 10 meters. It was regularly hauled up and 

 examined, and the larvae vrere also fed as regularly as the others 

 held on the surface. The experiments had the follov/ing results. 



On the 3d August 400 ne7;ly hatched larvae were set out in this 

 box. First on the 12th, thus after nine days, one single larva of 

 the second stage Y/as to be seen while amongst the larvae hatched on 

 the sane day that were put in. the surface box moulting to the second 

 stage had already beg\in three days earlier, on the 9th» Not until 

 the 5th were most of the lajrT-ae in the sunken box in the second stage, 

 some hovrever still in the first, these latter vrere therefore now 12 

 days old. On the 21st, five individuals of the surface box vrere in 

 the third stage (such a one had already been noticed in this stage 

 on the 19th) J Of those in -the sunken box however not one. Further, 

 on August 23, thus four days after the moulting to the third stage 

 had begun on the surface, among the latter the corresponding shedding 

 had not commenced. Of these only eight larvae remained in the second 

 stage, the others had gradually died; these eight v/ere .20 days old 



4 



