31 urine Aquarium, 



C231 



" Is not the earili 

 With various livijicr creatures, and the air, 

 Repleiiish'd ; and all these at ihy command, 

 To come and phiy before thee ? Know'st thou not 

 Their laniruaj^e and their ways ? They also know, 

 And reason not contemptibly. With these 

 Find pastime." 



Robert Swinhoe. 



Amoy. 



On Marine Molliisca in Aquaria. 

 By Charles Bretherton, Esq. 



The MoUusca are, generally speaking, ill adapted for the purposes 

 of ordinary aquarians. Though many are equal in beauty to the 

 handsomest zoophytes, the difficulty of preserving them has 

 effectually prevented their becoming popular. Many require parti- 

 cular attention or accommodation different from that of an ordinary 

 tank ; and as a group their habits are but little interesting, and their 

 actions monotonous. To those who devote themselves to the studv 

 of the Mollusca, the use of the aquarium is almost indispensable : it 

 is impossible to observe accurately their forms, except in their native 

 element, and in the small species this is a work requiring continued 

 study. To learn their habits and follow their metamorphoses the 

 aquarium is still more necessary. 



Observations on animals in aquaria usually consist of notes on their 

 peculiarities of habits, but shell-fish afibrd very little matter of this 

 kind, on account of the great uniformity and similarit}^ that prevails 

 among them in this respect. Like all marine animals, they require a 

 twofold sort of attention : in the first place, they require that the con- 

 ditions under which they naturally exist should be in some measure 

 reproduced in confinement ; and secondly, proper food. Most shell- 

 fish can be kept either in a vessel with sea-weed, and a bottom of 

 shingle or stone, or in one with a deep bottom of pure sand. It is 

 not advisable to combine the two, though often recommended. An 

 ordinary aquarium with a layer of sand at the bottom is more difficult 

 to keep clean, and never looks so well as one with shingle or gravel. 

 As a general ride, univalves should be kept on rock, bivalves in sand. 

 As to food, the bivalves and tunicaries are infiisorial feeders, and 

 require no attention whatever; the plant-eating univalves find food 



