
THE MARINE AQUARIUM. 263 
salt-water, dipped out of any pool among the rocks, only 
looking first to see that there is no dead fish or other evil 
matter in the said pool, and that no stream from the land 
runs into it. If you choose to take the trouble to dip up the 
water over a boat’s side, so much the better. 
So much for your vase ; now to stock it. Go down at low 
spring-tide to the nearest ledge of rocks, and with a hammer 
and chisel chip off a few pieces of stone covered with grow- 
ing sea-weed. Avoid the common and coarser kinds (fuci) 
which cover the surface of rocks; for they give out under 
water a slime which will foul your tank; but choose the 
more delicate species which fringe the edges of every pool 
at low-water mark ; the pink coralline, the dark purple rag- 
ged dulse (Rhodymenia), the Carrageen moss (Chondrus), 
and, above all, the commonest of all, the delicate green 
_ Ulva, which you will see growing everywhere in wrinkled 
fan-shaped sheets, as. thin as the finest silver paper. The 
smallest bits of stone are sufficient, provided the sea-weeds 
have hold of them; for they have no real roots, but adhere 
by a small disk, deriving no nourishment from the rock, but 
only from the water. Take care, meanwhile, that there be 
as little as possible on the stone beside the weed itself. 
Especially scrape off any small sponges, and see that no 
worms have made their twining tubes of sand among the 
weed-stems; if they have, drag them out, for they will 
_ Surely die, and as surely spoil all by sulphuretted hydrogen, 
blackness, and evil smells. 
your weeds into your tank, and settle them at the 
bottom, which last some say should be covered with a layer 
of pebbles ; but let the beginner leave it as bare as possible, 
for the pebbles only tempt cross-grained annelids to crawl 
under them, die, and spoil all by decaying; whereas if the 
-otom of the vase is bare, you can see a sickly or dead 
inhabitant at once, and take him out (which you must do) 
instantly. Let your weeds stand quietly in the vase a day or 
two before you put in any live animals ; and even then, do 

