8 



been departed from. The ecdj^sis and the pamng took place 

 m 1912, and the ripening of the ova and then fertilization early 

 in 1916. An mspection of previous reports on this subject will 

 indicate that crabs may come into berry {a) after the lapse of a 

 3'ear and some three months, (6) after two years, and (c) after 

 three years from the time of the ecdj^sis. The ecdysis in each 

 case follows normally the hatching of the eggs. Thus in the cases 

 just cited ecdysis would take place at the end of two, thi'ee and 

 four years respectively. 



As soon as the female becomes mature ecdj^sis is postponed 

 for a year. This condition is brought about by reproduction 

 reacting on growth. But it is evident that as the rate of growth 

 dechnes reproduction is obhged to wait on growth. This is a causal 

 relationship of the greatest interest. 



I wrote with reference to the lobster in 1912,^'' "It is plain 

 also with regard to the female that while at the onset of maturity 

 reproduction regulates ecdysis, the balance between growth and 

 ecdj^sis is restored after a few jxars Avhen tv, o or three ecd3^ses 

 have taken place. After that period ecdysis regulates sjDawning, 

 that is to say, when a size is reached when it is not possible to 

 complete sufficient growth to enable casting to take place 

 biemiially." These remarks aj^ph^ equally well to the crab, and 

 it is gratifying to find from the results of successive experiments 

 more and more evidence of the tact. 



From the facts which have been advanced it will be granted 

 that there is this relationship between ecdysis and growth, ajid 

 indeed the necessity for it may be said to be apparent. It is more 

 difficult to prove that growth and ecdysis are -also related to the 

 ripening of the ovarj^ that the ripening cannot take place until 

 some somatic relationship of growth in relation to ecd\^sis has been 

 satisfied. It might be urged that exceptions to the usual proce- 

 dure have been recorded. It has been ^^ointed out, for example, 

 that lobsters may become twice berried without -casting. The 

 examples which have been quoted are iew, and the proof has not 

 been adequate. On the other hand, however, all mvestigators have 



* Report, Dove Marine Laboratory, New Series, T., page 38. 



