REPORT OF COMMISSIONER OF FISH AND FISHERIES. 163 
laid from June 20 to July 15, and probably later; and in 1890, from 
July 1 until about August 20, according to the observations made. 
Lobsters do not breed readily when confined in close quarters. One 
female kept in a small aquarium for about eight weeks extruded eggs 
which were somewhat abnormal in their condition, and in the course 
of a few days they were scratched off by her from the swimmerets. 
The hatching period at Woods Holl occupies about eight weeks, be- 
ginning about the middle of May and continuing until near the middle 
of July, but it varies somewhat. In 1890 the last lobster with light- 
colored spawn (about ready to hatch) was taken July 7, and on the 
same day the Gay Head fishermen obtained the first lobster of the 
season with dark-colored or newly laid eggs. 
Prof. Herrick considers that the lobster does not breed annually, 
judging from the immature condition of the ovaries at the time@of hatch- 
ing of the eggs attached to the swimmerets, and by the large percent- 
age of non-egg-bearing females taken in the winter and spring. In 
April, 1889, 21 per cent of all the lobsters caught at Woods Holl by 
Mr. Edwards were females with eggs; in May, 19 per cent, and in 
June only about one-half of 1 per cent, the larger proportion of the 
eggs having hatched previous to, or during the early part of, the last- 
mentioned month. In the course of these observations it was also 
noticed that the females somewhat exceeded the males in numbers. 
Freshly laid eggs are very dark green in color, but toward the next 
spring they become wuch lighter, owing to the partial consumption of 
the yolk. The adult lobster may molt soon after its eggs are hatched 
(most commonly in the early summer) or not until fall, and possibly at 
any other time when not carrying eggs. ._The frequency of the fall 
molting has been referred to elsewhere. Prof. Herrick is inclined to 
think that, after becoming sexually mature, lobsters do not, as a rule, 
molt annually. From six to eight weeks are probably required to pro- 
duce a fairly hard new shell. At the time of hatching the larval lobster 
also molts for the first time, the delicate skin being cast off with the 
shell. This is a critical period in its history, and in connection with 
the work at Woods Holl large numbers die at this stage through ina- 
bility to pass the first molt. The young swim at the surface for six or 
eight weeks, when they attain a stage which bears a general resemb- 
lance to the adult, although differing from itin many details. The larva 
at this age both walks on the bottom and swins at the surface, but when 
it reaches the next stage, it leaves the surface entirely. 
During the early spring of 1890, Prof. Bumpus succeeded in hateh- 
jng lobster eggs prematurely by placing them in running water, of 
which the temperature had been elevated artificially to that of the sea 
water in June. The young made their appearance in a very few days. 
Other eges from the saine lobster retained in water of normal temper- 
ature did not develop appreciably during the same period. The young 
produced in this way seemed strong and hardy and no fatal results 
