36 



The observer looking into one of the Aquaria cannot but be 

 struck with the easy mode in which the Crabs, Lobsters, and 

 Crayfish move about, so different fi'om the movements of the 

 marine species on land ; this is due to the fact that their bodies 

 are in most cases only slightly heavier than the water, the weight 

 being thus taken off their legs gives them buoyancy. Some 

 species, of which there are several in the Aquarium, have their 

 hindmost legs flattened into paddles, with which they swim with 

 ease. A Crayfish of 5 lbs. weight weighs but 2 oz. in. water. 

 The Hermit Crabs have very soft bodies, and for this reason seek 

 the protection of a Whelk, or other shell; and I have always 

 found the shell was also tenanted by a red worm, about three or 

 four inches long, and not uncommonly by a Sea Anemone ; all the 

 species probably dependent on the Whelk shell to sustain and 

 protect them from injury in the struggle for existence. 



There are also some very small Crabs, common on the coast, 

 which habitually live in the shells of Muscles, Cockles, and some- 

 times Oysters, choosing often shells even smaller than the extent 

 of their outstretched legs, and always shells with the owner still 

 living in them, whose occupancy they do not disturb. 



I have often found these small Crabs in some numbers in the 

 IMuscles adhering to the wooden piles driven in to protect the 

 shore at Brighton. 



It would seem there is some mutual advantage, both to the 

 Crabs and the Sea Anemones, in these singular associations ; 

 selection is certainly shown on the part of the Anemone ; the 

 Parasitic Anemone always chooses a whelk shell inhabited by the 

 Bernhard Hermit Crab, but another species of Anemone, called 

 Adamsia, is found adherent to a shell inhabited by Prideaux's 

 Hermit Crab. 



The Eyed Anemone fSagarfia CoccineaJ is never found attached 

 to a shell inhabited by a Crab, but often attaches itself to the 

 shell of Turritella Communis, with its real owner still occupy- 

 ing it. I am naturally led on by these associations of Crabs and 

 Anemones to the consideration of the Sea Anemones generally. 



The extreme beauty of these lovely creatures, their general 

 resemblance to flowers, combined with the possibility of keeping 

 them in a very small quantity of water for years, caused them to 

 be kept in Aquaria at an earlier date than almost any other 

 marine creatures. 



I am inclined to'think it probable that the desire to grow these 



