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Part III. — 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 antennae, 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 iecess, 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 chelae 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. On July 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 chelae. 

 It was kept by itself until October, by which time it had become fairly 

 hard. A lobster that had just cast had both chelae, but was very soft. 

 The two were put together into a small tank. In a few days the soft 

 lobster was found dead ; its antennae, eyes, and part of one chela were 

 eaten off. 



