stage Yiv.s relatively long is explained bji- the fact t?io.t the temper- 

 r.ture wc.s then Ioit* On the 23rt of .June the majority of the Icrvne 

 hv\\ 7iro).^ressed into the 4th£bcge» 



This experiment was suddenly halted by the breaking of the 

 framing on the copper screen due to inferiority of this wartime 

 mr.terial. The young lobsters escaped and could not be counted, 

 an estimate of their mmbers wrs approximately 200© 



Soon after the end of this experiment, (the second rearing 

 tanlc could not be used because of the sliortage of available larvae) 

 a long drawn out period of bad weather commenced and the teiniperature 

 of the vjater fell to 13°« Under such circuinstances grovri:h is re- 

 tarded considerably and it took eight days to reach the second stage 

 while not less than seven days passed before the first larvae in 

 the third stage were noted. Hot a single one of the 6000 larvae 

 with which the experiment started, rtached the fourth stage altho 

 there vfere specimens among then of 20 days of age© After this cold 

 period the vreathcr improved, the coiu-se of the test started on 14 

 July is to be found in Table Vo The estimating of qu.antities was 

 done as ]:.r avx ov.sly described and on 21 July the seed lobsters vrere 

 removed from the rearing tanlcs« 



T/J3LE V 



Date Number Percentage of lai^T-ae ■ 

 of in the various stages 

 larvae in relation to the 

 total present 

 I if III IV 



2 Aug, 

 5 " 



3300 

 1300 



63 



32 

 100 



first in TJ stage 



IV are present, but fe\7 



are caught with the not 



The 4th stage vj-as, as shovm, reached in 19 to 20 days. The 

 figures of the total nu:.ibers reveal that a rather reg\ilar decrease 

 exists, disregarding the errors in obscrvationo Only tovfard the 

 end the numbers decreased much faster percentr.ge-vfise. This 

 occ\irs generally when the larvae are at the end of the 3d stage 

 and entering into the 4the In 1920 this also took place without 

 exception anl caused great damage. 



The reason for this is unlcnoT.Tn. to mce In the station at 

 Rhode Island, som.ething sim.ilar seems to have happened in 1920 but 

 mortality there vras definitely halted by transferring the larvae 

 to other, nev;ly cleaned tanlcs at the critical m.oment» According 

 to the mana,;er v.v Rhode Island the reason is to be found in lack 

 of sanitation. 



135 



