of the Fishery Board for Scotland. 101 
Ehrenbaum, but extends it to the middle of October. Meek found newly- 
spawned lobsters in July aud August. The lobster which spawned during 
Cunningham’s experiments in Cornwall did so in October, and Scott’s 
specimen extruded its eggs during the same month at Piel Laboratory. 
There is thus indicated an extended spawning season, including the 
months of July, August, September, and October. It may be that there 
are here two distinct groups of spawners—summer and autumn spawners— 
the first including lobsters that were not berried during the winter 
immediately preceding, while the autumn spawners are those which were 
berried during the winter, hatched their eggs in the summer, and extruded 
another batch of eggs in the autumn. 
The question whether or not the European lobster may carry external 
eggs two years in succession does not arise, Cunningham’s observation, 
confirmed later by Scott’s description of the process, having demonstrated 
that possibility. As for the American lobster, Herrick maintains, in a 
later work, the position taken by him on this question in 1895. He 
founds his contention that the American lobster does not carry eggs 
externally two years in succession on the condition of the ovary in various 
lobsters which had lately hatched the eggs. He maintains that the ovary 
requires two years to develop to ripeness. 
The factors which determine the spawning of the lobster are obscure. 
It is remarkable that only one lobster spawned in the Laboratory, 
although in several cases the ovaries of specimens which were dissected 
were apparently ripe. The rate of development ofthe ovary is dependent 
on some factor that is not apparent. The ovaries referred to would 
probably have been completely ripe in a short time. The complete 
ripening seemed to be inhibited by some influence, which might have 
been the absence or insufficiency of male lobsters. Even where a male 
lobster was present with the female spawning did not take place, and 
when the one lobster spawned no male was present. Otherwise the 
lobsters, it may be inferred, were under comparatively suitable conditions, 
for there was an uniformity shown in their history while in confinement. 
Moulting was common. What is the reason for the abstention from 
spawning? The artificially-supplied food may have induced growth 
rather than reproduction. 
The lobster may spawn the same year in which it has cast its shell. 
Trybom’s experiments* in labelling lobsters in order to determine their 
migrations indicated two females, measuring 84 inches long, liberated in 
June, had in November cast their shells and spawned ; they then measured 
a little over 9 inches in length. 
ae actual modus of spawning has been described by Coste, Scott, and 
others. 
Ehrenbaum describes a condition of the lobster which follows when a 
ripe lobster has been prevented from spawning. The eggs are absorbed 
and the blood becomes dark green or black in colour. The dark blood 
shows through at certain parts of the body and the lobster is known as a 
black lobster. Lobsters in this condition are found among those con- 
fined in floating boxes. The ovaries are much reduced in size, and the 
majority of the eggs have lost the green yolk, and have become of a 
yellowish colour. 
The Ripe Egg and the Formation of the Perivitelline Space. 
The ripe egg, newly spawned, was measured by Scott and found to be 
1-8mm. in diameter. 
*Fish Trades Gazette, July 30, 1904. 
