me 
1908] Decapod Orustaceans. 51 
In the case of Urangon vulgaris, which would seem from Erren- 
BAUM'S investigations to have two breeding-seasons in the year—one 
in the winter and one in the summer,—that writer has pointed out*) 
that in the winter breeding-season UC. vulgaris is ovigerous for 4 —5 
months; whereas in the summer, possibly owing to the higher tem- 
perature, the ovigerous period only lasts about four (or five) weeks; 
and that the time may perhaps even be shorter from when the female 
first becomes berried to when the larvae break out of the egg. The 
time required for development by the ova of Pandalus borealis seems 
to be practically the same as what FHreEn»Bavum says Is required by 
Crangon vulgaris for its winter period. 
I have never found an ovigerous P. borealis in the summer; 
and in all probability it does not spawn more than once å year, and 
is berried only in the autumn and winter: the ova taking, in the 
southern fiords at any rate, about five months for development and 
in the northern parts of the country perhaps a little longer. 
Moulting: Specimens may be found practically the whole 
year round which have just moulted; though this process generally 
takes place between the time when the females cast their spawn 
and when they again become ovigerous. During the period from 
the middle of March to the end of April we sometimes found in the 
Christiania Fiord that one third of å large haul consisted of prawns 
which had lately moulted and consequently were in å soft condition. 
All through the summer these soft prawns are to be found. - During 
a eruise made by the author from the middle of July to nearly the 
end of August they were constantly found, partly while still soft 
after moulting, and partly with a fairly firm though freshly formed 
shell of an intensely red transparent colour. Even as late as the 
middle of August a catch of 100 liters of Pandalus made in Gröns- 
fjord consisted almost altogether of absolutely soft individuals. In 
September, as already stated, the first berried specimens are to be 
met with. 
It is quite possible that, in the younger individuals at any rate, 
moulting takes place several times during the course of the year. 
Whether however the same is the case with the older prawns is 
mueh more doubtful. 
1) Dr. ErnsT EHrENBavm: Zur Naturgeschichte von Crangon vulgaris FAHR,, 
Mittheilungen der Sektion fir Kiisten und Hochseefischerei, Jarg. 1890 page 96. 
39 
