4 SPONGES 
GENERAL CONCLUSIONS. 
We find that a sponge is an animal with several sets 
of similar organisms, which are probably controlled by ner- 
vous force, and which act in harmonious concert in certain 
emergencies, Just as the organisms of higher animals act un- 
der like circumstances. Although reproduction is sometimes 
accomplished by buds, the young are mainly derived from 
ova, consequently the sponge is a Metazoan and nota Poly- 
zoan, where reproduction is accomplished wholly by division. 
There is thus considerable difference between the one- 
celled animals, classed as Polyzoans and the sponges, while 
considerable advancement has been made in the scale of 
animal life. 
On the other hand, there is also considerable differ- 
ence between the sponges and the Hydra, Hydroid polyps. 
and other polyps which constitute the next province above 
sponges, and which are scientifiically known as Coelindri- 
ata, 
