XVII. SrONGI2£. 
10 Spong. 
after a few hours, which appears advantageous, considering the strong 
tidal currents of its abode. 
Bidder (4) is of opinion that the differences between the bath Sponges 
of the Mediterranean and the Bahamas are not of a racial nature, but 
merely the consequence of the differences between the external influ- 
ences acting on the same species and variety. This view is combated 
by the Recorder in the Summary of Bidder’s paper (Zool. Centralbl. iii, 
pp. G88-690). 
According to Buck (11) species of Ephydatia thrive in aquaria much 
better than Spongilla. The gemmules produced in autumn should be 
dried, kept dry during the winter, and immersed in spring ; they will 
then produce a superior crop of Spongillids. He now no longer considers 
it advantageous ( vide Zool. Rec. 1895) to feed Spongillids with the 
microfauna of decaying salad-leaves. 
According to Weltner (55), Ephydatia fluviatilis lives through the 
winter in the Tegeler See, and in the Spree near Berlin, and does not, 
like other Spongillids, die after reproduction by the formation of gem- 
mules or ripe ova. In the Tegeler See specimens with ova occur all 
the year round. 
Marshall (32) makes some, mostly compiled, statements concerning 
the boring action of boring Sponges. 
McIntosh (34) states that boring organisms, amongst others also Vioa, 
attack chiefly the upper, convex shell of the Oyster. 
k. Artificial Sponge Culture (1, 2, 4 , 47). 
Bidder (4) states that Sponges attain a larger size when hanging down 
from some projecting object than when growing upright. Still more 
favourable it is for them if they are suspended from some floating thing. 
This is probably caused by the currents being more favourable in such 
localities, and should be taken into account when cuttings of Sponge are 
artificially affixed for the purpose of obtaining marketable bath Sponges. 
He also states what precautions must be taken if bath Sponges are to be 
transported alive from the Mediterranean to a distant place like the 
Bahamas. He fears, however, that the fine Mediterranean qualities of 
bath Sponges will, when transplanted to the Bahamas, probably acquire 
the same less valuable properties which characterize the bath Sponges 
indigenous to those islands. 
According to Allen (1), the bath Sponges from Florida are more 
regular in shape, and therefore more valuable, than the bath Sponges 
from the Bahamas. The difference between them is ascribed to the 
influence of the differences in the nature of the sea-bottom of these 
places. Experiments show that cuttings of Sponges grow much more 
rapidly in currents than in still water, and that the rate of growth (in 
currents) is much greater than that given by Buccich. In suitable places 
at Key West small Sponge-cuttings grow to four or six times their size 
in six months. 
Allen (2) reproduces a letter by Monroe, in which this gentleman 
gives his experiences on the artificial culture of Sponges in Biskayne 
Bay. Under favourable conditions, cuttings of about 16 cubic cm. 
attained twice this size in six months. Strong currents make the growth 
of Sponges more rapid, but cause their shape to become irregular and 
their texture harsh. Several hours of exposure to air does not injure a 
bath Sponge. A detailed account of how to affix and plant the cuttings 
is given. 
