138 Part ITI.—Twenty-first Annual Report 
collateral evidence furnished by the examination of berried females 
indicates that hatching takes place over a considerable portion of the 
year. 
F ay eggs hatched in the Laboratory on two occasions, viz. in May and 
uly, 
Several females spawned in the Laboratory at the end of September 
and in October. 
The Egg. When first extruded, the eggs are in the mass of a light 
orange colour; the single egg is straw-coloured. The eggs are nearly 
circular ; some are oval. Four eggs measured as follows, *375 :°37 :°37: 
3D X °4mm. 
an development proceeds, the colour of the egg changes to a deep 
amber. 
When the eggs are ready to hatch the amber colour has disappeared, 
and the mass is of a dirty grey colour. The change from the amber 
to the grey takes place not very long before hatching, probably within 
a month. 
The length of the period of incubation is not known. Meek suggests 
four months. This is very probably not an over-estimate. } 
Berried females may be got on the beach between tidemarks during 
nearly the whole year. The eggs on different females are in different 
stages of development, which indicates a more or less extended spawn- 
ing season. 
In January at Dunbar the eggs of a female were of a dark amber 
colour, and the eyes were present in the embryo. 
In April twenty-three females were examined at Dunbar. On the 
majority of these the eggs were of a dirty grey colour (ready to hatch) 
in five or six the eggs were of a light orange tinge. 
In May a considerable number have been examined at Dunbar and 
at the Bay of Nigg. One measuring 6 cm. across had eggs ready 
to hatch, and another 4 cm. had advanced eggs; seven had eggs of 
a light amber colour, and one of these measured just under 4 cm. in 
breadth. Of several crabs sent from the Dornoch Firth, two had 
orange eggs, while in the case of the others, hatching was proceeding. 
In a lot examined at the Bay of Nigg during this month the smaller 
females had advanced eggs, the larger had orange-coloured eggs. 
In June at Dunbar one of those found had eggs ready to hatch, half- 
a-dozen others had orange eggs. 
In July the eggs hatched in the Laboratory. 
In September, a female 6 cm. was found carrying advanced eg 
the eyes were formed. 
Females have been found with empty egg capsules attached in con 
siderable quantity to the swimmerets in May, June, and August 
These crabs had hatched their eggs shortly before capture. 
These facts then indicate that the hatching of Carcinus occurs over a , 
long period, viz. from April to end of July. Du Cane found that the 
eggs hatched in March. In putting the period during which the Zoéa 
of this crab may be found as from March to end of July, I do not 
think an over-estimate is made. 
The fact moreover that crabs having eggs ready to hatch, while others 
carry eggs which will not hatch for some time, are got simultaneously 
points to an extended spawning season. A 
The spawning season of Cancer pagwrus lasts three months, viz. 
November, December, and January. Hatching of this form took place 
at Dunbar in July and August, and at Bay of Nigg, August and 
September (end of). In 1902, while the eggs of certain of these crabs 
were hatching, the eggs of other individuals were still red, 
