234! Miscellaneous. 



of E. aspera died on the evening of the 1 7th, poisoning the tank, so 

 that on the morning of the 20th I found my poor Zoi-s dead, putting 

 a stop to experiments as far as they -^-ere concerned. 



The parent crab, however, still continues in health and vigour, 

 although the Avater has not been changed for the last six weeks, 

 and does not now consist of more than two pints in a circular tank, 

 six inches in diameter, and although two green crabs, C. mcenas, 

 during the time died from the poisonous effects of impure water. Its 

 habits are interesting : it is but a sedentary animal ; it seeks the 

 light occasionally, generally, however, keeping to the shadiest part 

 of the tank. At night it is most active, running over the sides and 

 bottom of the tank after the lights are extinguished, the noise it 

 makes being considerable as it rattles over the glass. Its mode of 

 feeding is sometimes most amusing. On its back, completely con- 

 cealing it, is a large mass of sponge, which of course the crab carries 

 about with it everywhere ; it, however, causes these strange pas- 

 sengers to pay toll occasionally, as I have frequently seen the E. aspera 

 stretching its long anterior limbs backwards, over its carapace, aud, 

 deliberately tearing off a portion of the sponge, coolly proceed to tuck 

 it in between its jaws : sometimes holding the jiiece of sponge in one 

 of the chelae, it daintily tears off small pieces from the mass, which 

 it then quietly devours. I detected it once feasting on a little Vary- 

 ing Iiij)polyte, //. varians, which was in the same tank ; but gene- 

 rally speaking, its food must consist of the Entomostraca aud other 

 minute animals, &c., which abound in the water, aud possibly also 

 the Ulva. It is a most sluggish animal, slow and deliberate in its 

 movements, and during the day remains with its back to tlie light in 

 a lair it has formed under a projecting piece of XJlva luctuca, its 

 long aud beautifully carved arms kept semiflexed at some distance 

 from each side of its body ; and the whole animal perfectly motion- 

 less, except an occasional vibration of the foot-jaws, looking like 

 some monster in his den. The species is not uncommon in mode- 

 rately deep water on the banks around the coast, and I would recom- 

 mend it as a good species to those who keep tanks, as it is generally 

 tenacious of life, and bears travelhng well, living for a long time, even 

 in a small quantity of water. 



jMy tanks, in which I have succeeded in keeping many of the rarer 

 Crustacea, are so convenient, and -their arrangement so simple, that 

 I am tempted to describe them. They consist of a number of what 

 are ordinarily called propagating-glasses (the dealers call them ' pro'- 

 glasses'), six inches in diameter, and nine inches high; the only 

 thing placed in them besides the water is the TJIva lactuca, selecting 

 a broad piece unattached to stones, as I find that stones harbour dirt ; 

 the sea-weed must be a large piece, as one of its chief purposes is to 

 afford cover and shelter to the animals from the light. It requires 

 to be occasionally renewed, as the animals feed on it. I seldom in- 

 troduce MoUusca of any kind, as I find them troublesome by dying 

 at unexpected times, and thus poisonmg the tank, and I have never 

 seen any occasion for their services in keeping my tauks cither clean 

 or healthy. 



