19 
THF CASTING OR MOULTING OF THF LOBSTFR. 
The followiim: observations were made by the Laboratory 
Attendant, J. A. Taylor: — 
f'astin”- is preceded by certain changes. The lobster 
gradually becomes dullish in colour, especially near the 
lower edge of tlie carapace. Aboiu twelve hours afterwards 
food is refused entirely. This is ])robably because casting 
has already begun in the forward region of the body, and 
feeding is no longei' possible. About half an hour before cast- 
ing actually begins the lobster lies evidently always on the 
left side. At this time the cei)halothoracic legion is being 
pushed backwards under the old cuticle, the aj)pendages lH*ing 
released as well, and the front ring of the abdomen is also 
gradually fi’eed. 'I'lien the back is lifted until the ce|)halo- 
thorax ;nid abdomen are situated almost at right angles to one 
another, d’he lobster by these o|>erations biings pressure 
enough to burst the very thin cutitde l>etween the 
cephalothorax and abdomen, and by a continuation of them 
it gradually [)ulls the forward region clear of the carapace 
until a hold or ])urchase is obtained on the posterior edge of 
the carapace for the rostrum. AVith this as a lever the for- 
ward appendages are slowly released, the thin posterior 
pereiopoda and then the large cdielae. All this forward part 
freed, the lobster practically walks out of the obi shell, 
releasing the abdominal portion as he does so. The time 
taken in casting varies from eleven to twenty-three minutes. 
It might be suggested that the armature of the rostrum 
may therefore have some physiological relationship to 
casting. 
