INSECTS. 233 
both dilatation and contraction ; and the whole body 
is a continuation of rings and joints. 
43. Under the skin there is a slimy liquid, which * 
the reptile ejects when it is required, and which fa- 
cilitates its passage through the earth. 
44. It has breathing holes, which run along the 
back ; but it has neither bones, eyes, ears, or brain ; 
and the heart is placed close to the head. 
MADREPORE AND CORAL. 
45. Among the zoophyte class we may just men- 
tion the Madrepore and Coral tribes, the minute in- 
sects composing which form reefs and islands of im- 
mense magnitude in the Southern Ocean. 
46. A very considerable part of the coast of New 
Holland is bordered by reefs of their construction, 
which rise to the surface from a vast depth. 
47. Coral is generally obtained from the Mediter- 
ranean, but the most valuable is that of the East ; it 
being larger in size and more compact in substance. 
What insects construct the reefs of Coral in the Southern Ocean 1 
Where is Coral obtained from 1 
20 * 
