75 



NOTES AND MEMORANDA. 



1. Hermit Crabs and Anemones, &c — It is often so difficult to 

 make systematic observations on tlie inter-relations of animals, that 

 a bare record of the merest fact may prove eventually to be of use. 

 These few lines, on one or two small occurrences in the aquarium 

 and elsewhere, are printed here, not from any intrinsic interest, but 

 in the hope that they may be useful to some future worker. 



Upon the relations existing between certain Actiniaus aud Crus- 

 tacea, observations are much needed. In a tank containing several 

 Pagurus Bernhardus and Adamsia Rondeletii {Sagartia parasitica) , 

 which are habitually associated in a form of commensalism, most of 

 the Paguri for one reason and another died, and their anemones in 

 some cases crawled off the shell and throve independently (this has 

 been noticed also in the case of Adamsia palliata). One of three 

 specimens of 3£aia squinado living in the same tank, presently 

 appeared bearing first one, then two, finally three Adamsia Rondeletii 

 on its walking legs ; one, if I remember right, was placed on the first 

 walking leg of each side, the third on the second leg of the right 

 side. The limbus of the anemone was in all cases firmly clasped 

 round the leg, the edges meeting closely in the manner of Adamsia 

 jpalliata. The anemones remained in this position for some days, 

 but only one was left after about a month. Though the crab was 

 not actually seen to place the anemones on his legs, there can be 

 little doubt that such was the case, both because the anemone's 

 power of locomotion is but small, and because of the well-known 

 habit of Maia to " dress " itself with anything available. On the 

 other hand cases are known where the anemone, whether as embryo 

 or adult, selects its own habitat. Last summer in the aquarium a 

 particularly fine specimen of A. Rondeletii was fixed on the back of 

 a large live Buccinum undatum ; and under the same head probably 

 fall the Rondeletii on the cephalothorax of Carcinus moenas, instances 

 of which are occasionally dredged in the Sound. In another tank 

 where Pagurus Bernhardus with Adamsia were stored, when the 

 anemones were fed the hermit-crabs were frequently observed to 

 insert a chela into the stomatodseum of the anemone associated with 

 another crab, and to drag out and devour the plunder. Mr. 

 Bateson recorded some time ago in this Journal that he had noticed 

 a prawn rob an Anthea in this way, and the observation has been 

 since repeated. 



