THE REPRODUCTION OF THE LOBSTER. 63 



latter half of July, whilst they were numerous, but all were at least in 

 the nauplius stage, in October, would seem to show that August is the 

 month during which most of the females spawn. Development during 

 the winter months took place very slowly. 



The first lobster which I was able to obtain during the following year 

 with eggs on the point of hatching, was brought to the Laboratory on 

 the 20th of March, and larvae were set free on the 29th of the same 

 month. This lobster, which was stated to have been taken in deep 

 water off the Eddystone, appears, however, to have been quite ex- 

 ceptional, for, in spite of repeated endeavours, no specimen could be 

 again procured with ripe eggs until the middle of May. From this 

 time they became more frequent, the largest number being obtained in 

 June, By the middle of July only occasional specimens were seen, 

 whilst after the end of that month no more could be obtained. During 

 the last fortnight of July the two seasons appeared to overlap, very 

 few lobsters being in berry at all ; whilst of those which were, the 

 number having ripe eggs appeared to be about equal to that of those 

 whose eggs were newly spawned. 



On the whole, therefore, it is probable that, in this district, the 

 majority of lobsters lay their eggs during August, and the majority of 

 eggs are hatched during June, the period of fosterage being at least ten 

 months. 



Coming to the question of the interval which elapses between the 

 hatching of one brood of eggs and the laying of the next, the authors 

 are agreed that this must be at least a year, whilst Ehrenbaum would 

 make it considerably longer. The reasons brought forward by the 

 American naturalists in support of their conclusions on this head are, in 

 the first place, the immature condition of the ovaries of females which 

 have recently hatched their eggs, and the slow rate of maturation of 

 the eggs in the ovary, which render it impossible that the eggs should 

 be ready for laying during the summer in which a brood has hatched ; 

 and, secondly, the fact that during the winter months a large proportion 

 of the females captured do not carry eggs. 



As already stated, Ehrenbaum makes the interval much longer, and 

 considers that, on the average, a female lobster produces eggs only once 

 in four years. This result is so extraordinary, and if the conclusion 

 can be maintained, is so important, that it is worth while stating in full 

 the evidence on which it is based, and I give, therefore, the following 

 translation of Ehrenbaum's remarks on the subject : 



" If eggs were laid every year, then, in consequence of the long dura- 

 tion of the hatching period, females bearing no eggs on the abdomen 

 would seldom occur, which is by no means the case. It can rather 

 be proved with tolerable certainty that the intervals between two 



