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Part III. — Twenty-third Annual Report 



(9) A third specimen of the 1902 stock which had cast in 1903 was 

 kept until February 17th 1905, when it was found dead. The ovary was 

 large and black. The eggs appeared to be ripe, and had at one pole a 

 clear green cap. 



(10) The last survivor of the 1902 lot died on April 2nd 1905. It 

 had cast in 1903 and also in 1904. The ovary was large, black; but 

 otherwise the lobster appeared to be poorly nourished. 



Hard Lobster. 



A lobster which was not berried when captured was dissected on 

 December 1st 1903. It measured 11 inches in length. The shell was 

 clean, black. The ovary was black. The eggs were yolked, but only 

 about half the diameter of ripe eggs. The eggs separated fairly freely, and 

 measured 1 x "8 : '72 x '65 : 1 x '9mm. These were black yolked eggs. 

 There was also a considerable quantity of white eggs, all small and of 

 various sizes ; the largest of those noticed was oval, and measured 

 '45 x '3mm. 



Meek records a lobster measuring 11^ inches in length which hatched 

 its eggs in the beginning of July and lived till September 12th 1901. 

 The ovary was dark green, and was well developed. It exhibited no signs 

 of preparation for casting. 



Spawning. 



Of all the adult female lobsters which have been kept at the Laboratory 

 during the past three years, only one was known to have spawned. Some 

 of those which were from time to time dissected had ovaries which were 

 practically ripe. The lobsters were kept for longer or shorter intervals. 

 One batch of females which were berried in 1902, and which hatched 

 their eggs in the summer of that year, were represented at the Laboratory 

 till April 1905. No member of this group showed any eggs attached 

 externally. That they were not altogether unhealthy was shown by the 

 fact that they nearly all moulted once, in two cases twice, during the 

 period named. So it was with the other females ■ they cast readily, but 

 did not succeed in spawning, or, if they spawned, the eggs did not 

 become attached. Moreover, none of those dissected had a spent ovary. 

 In the case of the adult crabs some spawned, but in one or two of these 

 only a few eggs became attached. 



The lobster which became berried was received from Dunbar in 

 December 1902, at which time it was not berried. It cast its shell on 

 September 2nd 1903. On January 13th 1904, when it was examined, it 

 was not berried, but on July 14th a small quantity of eggs were found 

 attached to the swimmerets. The eggs were early and apparently just 

 spawned ; they were dark-green with a clear granular area on one side. 

 This lobster was not with a male lobster when it spawned. On October 

 21st 1904 there were only two eggs remaining attached, and when it 

 was examined on November 19th 1904 the remaining two had dis- 

 appeared. 



As to the time when spawning takes place, Ehrenbaum gives the 

 period covering July, August, and probably September. Fullarton 

 obtained lobsters with very early eggs — yolk nnsegmented — between 

 July 18th and August 25th. Herrick says, for the American lobster, that 

 the definite spawning season is the summer, July and August, but that a 

 minority extrude their eggs in the fall and winter, if not also in the 

 spring. Allen obtained females with freshly extruded eggs during the 

 latter half of July. Appellof agrees with the period announced by 



