50 REPORT OF COMMISSIONERS OF INLAND FISHERIES. 



Towards the end of the stage, however, they seem to function with 

 less ease, and the late third stage larvae swim about more sluggishly. 

 This is no doubt largely due to the important and marked changes 

 which are taking place within the young lobster as the moulting 

 time draws near and it prepares to enter the fourth stage. It is 

 quite probable that the atrophy which, after the third moult, is 

 noted in the exopodites of the ambulatory appendages and cheli- 

 peds, even now in the latter part of the third stage, is retarding the 

 function of these swimming appendages and resulting in the periods 

 of suspended activity which is a phenomenon less often observed in 

 the earlier stages. The following are notes from a record of ob- 

 servations made upon individuals of the third stage to determine 

 whether or not in their activities they showed any signs of adopting 

 in swimming the habits so characteristic of the following stages : 



June 11, 1904. About 20 third stage lobsters nearing the time of 

 moulting w^re placed in a Daniell jar. They swam somewhat less 

 actively than individuals of the second or of the early third stages. 

 Normal attitude in swimming was with head and cephalo-thorax 

 bent downward at an angle of about 45 degrees from a horizontal 

 plane. The abdomen was usually bent downward to a somewhat 

 greater angle. Ofttimes, however, the tail would be straightened 

 out, sometimes slowly with no apparent change in the position of the 

 individual, and again verj^ suddenly, the motion usually resulting 

 in sending the young lobster toward the bottom of the jar. At other 

 times, the tail segments would undergo a rapid contraction, thus 

 sending the young lobster backward with a sudden jerk. This latter 

 action was the most common. The swimmerets were motionless in 

 the process of straight forward swimming, but in the backward 

 jumps, they w'ere more often used together with the tail. The ex- 

 opodites of the leg sand cheliped seemed functions •with, greater 

 difficulty than in the earlier stages. It was also noted that very often 

 the exopodites would cease their vibratory motion, and, as if in a 

 period of exhaustion, the young lobsters would sink to the bottom of 

 the jar. Here they would lie for some little time quite motionless 



