of the 5th str.ge is put r.t r;bout 20 days. Hnving then reached the 

 6th stage., it he s a length of 19 rrm.j ngair. after approximately 20 

 days it changes into the 7th stage vdth a length of 22 inmc In this 

 stage the first abdominal appendages appear, in the 8th stage these 

 have devuloped so far that they wake possible the differentiation 

 of the se"xes» AocordinL, to Jorgensen, the first abdominal appen- 

 dages appear still later and indeed approximately in the 10th stage. 

 Lobsters bor; late in the yoor enter vrinter-rest already In bhis 

 stage, the earlier born reach yet the 10th, or 11th stage v;ith a 

 length of 35 or 42 r^ric respectively* All numbers nentioned ?icre 

 'are taken from aquariusa experiments vdiich are almost wholly with- 

 out confirimtion by observations in the vfilde Small lobsters of 

 less than 80 Tnia« length almost never cone to sight; that hovrever 

 roany young ones spend the winter at a length of 40 iim« results 

 from the fact that some snr.il lobsters v/hich vrere cauglit in v/inter, 

 had approxiLr.tcly this lengths In the. vdnter , gro-.'rt;li strands still. 

 In their second s uirccier-'^to understand diuring s uimner is the t5.ne of 

 groxrth— the lobsters moult approximately "ive ti;.'.es and are, at the 

 beginiiing of the second winter, in the 13th to 15th stage and have 

 a length, of from 65-cO mi!i« Vfhen they have shed yet once in the 

 spring and have attained v. length, of 90 mm., they are already 

 captiired in the lobster fishing apparatus. In the 3d siuoraer thoy 

 mou" . two or th;"ee tines aud are, at the beginning of the 3d 

 winoer in the 16th to 18th stage at a length of 10-12 cms In the 

 4th summer tvro moults probably follow, in the 5th perhaps also 

 still, in rxmy cases hov/ever only one more; in the 4th and 5th 

 winter the length is 16 end 22 oi.ir> If they have reached these 

 last si"es, they then shed not oftener than once in a yearo 

 Directly after the following moulting, the females can have reached 

 sGxual Liaturity and become natodj in the follovn.ng summer, they 

 then for the first tine extrude eggs. The females do not shed in 

 the 7th summer £ but not again until the 8th; moulting and egg-laying 

 then alternVite with each other every s-anner still farthers The 

 iTiales still however continue every year in doing so,, each su>nmer to 

 shed once and mr.intain thus an advantage in grovfth over the females. 

 The above mentioned nuiabers are for the most part taken from a \;ork 

 of Ehrenbaun (47) who succeeded in observing in an aquarium for 

 three years o. lobster raised from the egg and collecting thereby 

 all the cast off shells o 



The accounts of the grov.'th of the older animals depend princi- 

 pally upon marking experiments (Dannevig 37 _, 37a) and direct obser- 

 vations of the shedding of caught lobsters o All figures are hovrever 

 only to be interpreted as approximate values, which become influ- 

 enced by mraiy factors. For the first year it is of importance in 

 what tine the larvae are born; early born ones experience in the 

 first year four or five stages more than later' born ones« Also not 

 each stage is characterized by a definite length. In reference to 

 the artificially reared 4th stages it is noteworthy that the diff- 

 erence of grovrth can become evident up to 30 per cent, also, for the 



147 



