American Fisheries Society. 239 
some weight. If the sponge be loose on the wire, its rotation 
causes an enlargement of the perforation through which the 
wire passes and there is also a waste of growth energy in the 
necessity for the readjustment of the canal system. If a sponge 
be inverted, there is tendency to the closure of the original oscula 
and the formation of others upon the new upper surface and if 
the processes of inversion be frequently repeated, as when the 
sponge is free to rotate, growth is retarded by the necessity for 
repeated readjustment. 
When lead-covered marline is used, within a week after they 
are planted, the cuttings have attached themselves and become 
permanently oriented with respect to their supports. At the 
time of writing, lead covered marline has been in use for nine- 
teen months and is in a good state of preservation. Several lines 
have broken near the stakes to which they were immovably at- 
tached, but a more flexible attachment has prevented the re- 
peated flexure of the lead under the movement of the waves and 
since its adoption no trouble has been experienced. Asbestos 
coated with paraffin and asphaltum and encased in lead has been 
used in the same manner and with practically the same results. 
Several forms of lead-covered insulated wires have been em- 
ployed, but the ordinary commercial sorts have been unsatis- 
factory, being either too heavy, or, if sufficiently hght and cheap, 
lacking in durability. A specially made wire with underwriters 
insulation encased in lead appears satisfactory after several 
months of trial, but it is somewhat more expensive than the lead- 
covered marline. In this material, also, a rigid attachment to 
the stakes causes the lead covering to break near the supports 
owing to the repeated flexure of the wire as it sways with the 
waves. The attachment is now made by means of a stirrup- 
shaped bridle of copper and wood. This was a makeshift device 
and while it answers the purpose, cheaper and more durable 
arrangements with be adopted in the future. 
The experiments have not reached a definitive, stage and 
some of the mechanical problems have not yet been solved. It 
is not yet even determined if a sufficiently large proportion of 
the cuttings will grow to a marketable size to warrant the em- 
barkation of capital upon the venture of sponge growing. 
In these experiments as in their predecessors it has been found 
