SPONGES 49 
Since the foregoing was written, I have found this species in other portions 
of Nassau Harbor, but never in abundance anywhere. 
I have been often asked whether I think that a sponge is an individual or 
a colony of individuals. From the point of view presented by individuals, as 
sve see and understand them, in the vertebrates, or even in the higher inverte- 
brates, the whole matter of individuality in the low forms ts which the sponge 
belongs, is difficult to understand, but wecan say that a careful consideration 
of the foregoing array of facts will certainly lead us to the irresistable conclu- 
‘sion that, whether or not we regard each cilia cell, or a number of these cells, 
as constituting a separate individual, equivalent, for example, to a coral polyp, 
the water system andits accompanying cilia cells, at least combine together in 
emergencies, and with common sympathies and common energies act as the or- 
ganisms of a single indiydual throughout the whole sponge. 
COLOR OF HORNY SPONGES. 
Although in this group the colors are notas brilliant as in the spiculige- 
nous species, there are some among them which are quite brightly colored. 
Sponges belonging to the genus Verongia, of which the Tube Sponge is a mem- 
ber, are highly colored.Orange, bluish, and malachite green are among the col- 
ors with which these various species are ornamented. Anexample of the color 
of the Tube Sponge is given on PlatelJ, and on Plate I) will be found an ex- 
ample of the same species when dried 
All of the commercial species are glossy black externally when living, and 
dull black when dried with the fleshon. The interior of some of some of the 
