96 Part LII.—Twenty-third Annual Report 
claw it very often has to yield it up, whereupon the other unconcernedly 
drops it. Lobsters which have been confined together show many traces 
of the attentions that have been paid to one another. The chela is, in 
many cases, missing, or, if it persists, has one or more scars of bites, which 
had crushed through the shell. Very few of the lobsters have anything 
but short stumps of their antenne, these organs having been snipped off 
more or less close to the head by their companions. These accidents 
usually happen when the lobsters are wandering about seeking for dark 
corners and sheltering holes. After they have settled down in their holes 
they stick to their habitations and do not come so much into competition 
with one another. When they are first introduced into a tank it is well 
to have the big claws tied, and by the time the claws work free their 
owners will have settled down in their new quarters. If there is suffi- 
cient accommodation in the form of holes of inviting darkness, they will 
soon get peacefully distributed ; but at first a lobster will sometimes try 
to evict one lobster from the hole which it has selected as its abode. One 
lobster was seen to yield up the recess, which was immediately taken 
possession of by the aggressor. 
On each occasion when the tank is emptied for cleaning, and for the 
purpose of examining the lobsters, it is usually necessary to disturb the 
shelter-holes, which are formed with stones. When the tank is filled 
again the lobsters do not seem to recognise one another at once. They go 
cautiously about seeking shelter, on the watch for foes and ready to fight 
any lobster they may meet. Under such conditions, then, it is not 
surprising that chel are lost, or some other injury incurred, before they 
are all satisfied as to hiding accommodation. When they settle down they 
allow for one another’s presence and get on without quarrelling. This is, 
of course, due to a healthy respect which they have for one another’s 
fighting powers. The truce is nothing but an armed neutrality. If any 
one of the lobsters loses its fighting power through casting its shell, it is 
at once attacked. And that occurs in cases where lobsters have lived 
together for months. Four lobsters were in a large tank undisturbed 
for four months. When the tank was emptied each lobster was handled. 
Two days after the tank had been refilled the chela of one of the inmates 
was lying loose on the sand. 
More especially do the lobsters take advantage of any one of their 
number that casts its shell. Very seldom does the soft lobster escape 
without serious injury. Female lobsters attack a soft female. The male 
which cast in November 1904 was so injured by the female which was with 
it in the tank that it bled to death. How a male would act towards a 
female that cast in its presence was not indicated during the experiments, 
as that case did not occur. 
A female lobster that cast on July 13th 1904 had a hard male lobster 
introduced into the box in which it was. The male did not appear to 
mind the listless and inactive female; it certainly did not attempt to 
grasp it or fight it. OnJuly 19th the female was found to have been 
bitten in the cephalic region ; one chela had been lost and one or more of 
the remaining pereiopods bitten off. This is very different treatment to 
that meted out by the male crab to the moulted female. In the latter case 
the male protects her, 
The extremely defenceless condition of the soft lobster was especially 
seen in one case. A female that moulted in August had lost both chele. 
It was kept by itself until October, by which time it had become fairly 
hard. A lobster that had just cast had both chele, but was very soft. 
The two were put together into a small tank. In a few days the soft 
lobster was found dead; its antenne, eyes, and part of one chela were 
eaten off, 
