308 TlMEHRI. 
port, and generally opening out beneath the individual 
polyps in the form of small cups, in which the little beings 
reside, and over the sides of which they can expand them- 
selves with a striking resemblance to fragile blooming 
flowers, thus increasing their apparent similarity to 
plants. In the group of the Sponges (Spongida) , the 
body mass or colony is not covered externally with hard 
structures, but throughout the soft substance an abundant 
skeleton extends, either in the form of united horny 
fibres or in grouped bundles of calcareous or siliceous 
needles or spicules ; and this skeleton is sufficiently firm to 
preserve the form of the colony after its death and the 
decay of its soft structures. Lastly in the group of the 
Corals (Anthozoa) a more or less massive or branched 
skeleton, or coral, is present beneath the outer fleshy layer 
by which it has been deposited, and continuous with the 
soft bodies of the star-like polyps which make up 
the colony. In all cases, these skeletal tissues of 
the Zoophytes are the only parts that survive after 
the death and decay of the colony ; and they give 
no idea whatever of the structure of the little soft 
bodied beings by which they were produced. The 
sponges of commerce are thus but the bare support- 
ing framework of what during life was the true sponge 
colony. 
Throughout the greater part of the world, the observer 
by the sea has within his reach a boundless variety of 
these strange and beautiful forms of life. They inhabit 
the shallow waters either floating, conspicuous in their 
radiant colours, on the bosom of the sea, or nestling like 
fairy flowers in the recesses of some sheltered roci<- 
pool, or spread out like a gay parterre on the gentle 
