hns bee one lovrer v .dth Tirhich the first groT/bh period, rrhich neans 

 the !j;r ovrbh of the first yer .r of life, is t eri.iinr.t ed » The smr^ll 

 lobster is now thre e to foiu* months ol'.l, has noulted five to' six 

 t ines_ cind_ j. s now in its 6tlT^ or .7th stag_e» In gen eral it has a 

 length of from 19-2_2 inm,, ■ except ionr.lly even 26 ctii. 



. (page 62) 



■ (page 78) ' , 



As for the youngest stages the inost detailed researches hrve 

 been made by Ehronbaun at Hel^roland and by English scientists on the 

 British coasts. Ehrenbaum (2) points ont that the d\jration of the 

 first three stages depends in a high degree on the temperature of 

 the water. Hence it is also evident tliat the larval s t ages in the 

 Helgoland ^''istrict, v/hore the mean tcnperct'ore of the v:ater in 

 August, the m-nth when most of the lobster, larvae pass through their 

 development J is approximr.tely 16.8 C, vj-ill develop in a somewhat 

 shorter time than on our Ifest Coast vrhcre the mean temperature in 

 July and August is approxiiTiately 15-16° C, Naturally Ehreribaun 

 carried on his rearing experiments in the aq\iari\im of the Biolo,;ical 

 Station where according to his data the temperature rises up to 

 18-20° C. and t he results Virhich he obtained here show consequently 

 a quicker grovfth also than would have been the case in all prob- 

 ability in the open sea. For all tl-iroe larval stages in the Helgo- 

 land AquariujTi 12 days vrort. required in the shortest case and in the 

 longest, 19 days. In earlier experiments, ;ilso Helgoland, Elirenbaum 

 (2, pe 150) has required however a somevriiat longer period for the 

 first tliroe stages, namely 19-22 days, in r egard to the duration 

 for each stage El-irenbaur.i declares the follov/ing numbers: 1st stage 

 4-5, 2d stage 3-5, 3d stage 5-10 ^:ays» For the 4th stage, Ehrenbaun 

 found a duration of 17-25 days, according to the season. 



On an average therefore the development during the larval stages 

 proceeds more qxxickly in the southern part of the North Sea than on 

 our Hest Coast. Also the difference of the later, younger stages 

 is to be noted. El-irenbaum has had the opportunity to observe an 

 individual during three groTfbh periods. Instead of the average of 

 the lobster larvae on oui' West Coast in the first period only reach- 

 ing the 6th or 7th stage with a m.can length of 19-22, highest 26 :.-an., 

 one individual reared nt Helgoland reached the 9th stage and a 

 length of 30 mm. In the follovj-ing .;rovrt;h periods the grovirbh also 

 is much quicker so that, the mentioned individual at the end of the 

 3d groirth period had ri-ached the same size of 11«5 cms. that the 

 individual reared at Kvittings/ had at the end of the 4th. It is 

 to be noted that the nuiTiber of sheadings for each of the three 

 periods was greater than on the West Coast of Norvray, namely eight 

 in the 1st, five in the 2d and four in the 3d period. The literature 

 mentions only this single individual v/hich, outside of Norway, had 

 been reared fr^m the larval stage to over so large a number of 

 periods. However, El-irenbaujia has found that also at Helgoland Ir.rvae 



