ELISHA MITCHELL SIENTIEIC SOCIETY 82 
When, however, the animals were confined in a large box 
anchored in about a fathom of water, quantities of devel- 
oping eggs could be had by drawing up with a tube some 
of the sediment in the bottom of the box. 
The ‘‘spat’’ ouce obtained in abundance, success will 
next depend largely on the <election of the locality in 
which the young sponges are to be set out. A careful 
study of the Florida grounds should be undertaken, with 
the view of investigating, among other points, this very 
matter of the kinds of locality best adapted to the growth 
of the various grades of sponges. Quiet water,a firm 
bettom, and an absence of muddy sediment seem essential 
desiderata. The question of enemies is probably of minor 
importance, and yet the well-known student of sponges, 
Vosmaer, mentions that he has several times seen the Kuro- 
pean hermit-crab( Pagurus) greedily eat a common silicious 
sponge (Suberites), certainly quite as unappetizing a 
morsel as the commercial sponge. 
When it has once been accurately determined what are 
the physical and biological characteristics of the Florida 
grounds, which produce the finest sponges—and it may 
be mentioned here that sponges are among the most varia- 
ble of animais and seem to be peculiarly affected by their 
surroundings—a detailed comparison should be made be- 
tween these grounds and those parts of the Mediterra- 
nean producing the finest grades. The purpose ofsuch a 
comparison would be to discover whether we really 
lack any of the natural advantages necessary for 
the production of the finest sponges, and if so, 
whether these can be artificially reproduced—whether 
for instance it would be possible or desirable tu imitate on 
this sidea particular kind of bottom found in the Medi- 
terranean. 
Following on the investigation of the sponge-grounds, 
