REPORT OF COMMISSIONERS OF INLAND FISHERIES. 73 



SUMMARY. 



Changes of Form in Successive Stages. 



The life of the lobster consists of a series of stages (the first four 

 are called the larval stages) each of which represents a stage-period, 

 the time between any two successive moults. The lobster grows by 

 moulting, never between moults. 



The changes which are undergone in the first four stages are the 

 most distinct. After this period the changes in form are slight from 

 one stage to another. 



First Stage. 



Owing to the much coiled position in which the young lobster lies 

 in the egg, at the time of hatching this infolding of appendages and 

 abdomen about the head is very apparent and endures for some little 

 time; gradually, however, the parts extend and the appendages 

 become functional. The characterisitic points of the first stage 

 lobster may be briefly summarized as follows : 



1. Dorsal surface of cephalo-thorax in lateral aspect forms a 

 decided arc. 



2. Eyes very large and prominent. 



3. First pair of antennae consist only of exopodites. 



4. Second antennae consist of exopodite and endopodite, the 

 former very short and tubular, the latter broad and leaf-like. 



5. The thoracic appendages have feathered swimming attach- 

 ments (exopodites). 



6. The body-origin of the thoracic limbs is posterior to position 

 in adult type. 



7. There are no appendages on the ventral portion of the abdomen. 



8. The tail, after unfolding, consists of a simple "tail-fan." 



9. The average length of the first stage is 8 mm. 



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