of the Fishery Board for Scotland. 



97 



Peculiar Action of a Group of Lobsters. 



On October 29th the four female lobsters which cast during the 

 summer were very restless. They were walking about in the tank, or 

 standing, as it were, on tip-toes, and having the abdomen bent, with the 

 edge ot the telson close up against the fifth pereiopod. Occasionally they 

 extended the abdomen and moved the swimmerets backwards and forwards. 

 The male lobster which is with them was also out of his hole, standing on 

 tip-toes, with the abdomen extended straight out and moving his 

 swimmerets actively. The lobsters appeared to be quite friendly, and 

 did not attempt to bite one another. The supply of water running into 

 the tank was not very large at this time. Whether this had in any way 

 influenced the action of the lobsters is an open question. It had not 

 been observed before. 



The Senses of the Lobster. 



The lobster when it walks has the telson turned in on the abdomen, 

 and it marches on the " points of its toes," backwards as well as forwards. 

 It is practically blind ; it sees nothing properly, at least that is the 

 case where it is exposed to the comparatively strong light which 

 during the day illumines the tanks in the Laboratory. It has 

 simply the sensation of light and shadow. It tests a shadow 

 with its antennas, or sometimes where a strong shadow is thrown 

 on it, it jumps at it with its chelas outstretched and snapping. It 

 is dependent on its antennas for guiding it in safe places. It is 

 especially careful in testing any hole before it is satisfied with it. It 

 discovers the cavity by means of its antenna, which is waved well out 

 to the side and in front as it walks. It searches the innermost depths 

 of the hole with the antenna, and then inserts its chela. If the examina- 

 tion with the chela is also satisfactory, it immediately turns and backs 

 smartly into the hole. In feeding it is guided to the food by the 

 antennules. A piece of food which is dropped near a lobster may fall 

 quite unnoticed unless it happens to touch the antenna or the pereiopods. 

 It is not seen at all. But sooner or later, according as the distance is 

 short or great, the scent of the food, carried by the currents set up by. the 

 exopodites of the maxillipedes, reaches the lobster. The lobster is 

 immediately excited, although previously it was lying quite inert in its 

 hole. It whips the water with its antennules in a staccato fashion, and 

 feels about with the antennas and chelae ; at first without leaving its hole. 

 At once both antennules are seen to be whipping in the direction in 

 which the food is lying, and an active search is made with the antennas. 

 If they do not succeed in locating the bait, the lobster rather reluctantly 

 leaves its hole, but cautiously, feeling all round about with its antennas. 

 It goes off straight in the direction in which the food is lying, and if it riiisses 

 it with its antennas and chelas, walks over it and gets it with its chelate 

 pereiopods ; it usually picks up its food with the second pereiopod. 

 Meanwhile the expected feast has by association stimulated the maxilli- 

 pedes, which are actively working as if they were already masticating the 

 food. Once the food is seized it is conveyed to the maxillipedes, and the 

 lobster retreats to its hole, there to enjoy its meal. Two lobsters were 

 noticed to have stored up in one case some mussels, in the other a dead 

 sand-eel {Ammodytes tobianus), in the inner recesses of their caves. 



Effect of Cold on Lobsters. 



In the winter the lobsters kept in the tanks of the Laboratory became 

 very sluggish, and ate very little if any food. "When taken out of the 

 water and exposed to the frosty air they become very inert, 



