Re: Functions of the coelom?

You point out a common problem of most basic Biology Texts. Many books hardly ever go into 
detail about the important reasons of why the coelom is important. Actually, you are better off 
looking through an Invertebrate Biology text book, as body cavities are heavily discussed.

The body cavity has many uses:

1) The coelom cushons organs from internal injury. This is because they are not directly attached 
to the outer body.

2) In soft-bodied animals (earth worms) the fluid filled coelom functions (when under pressure 
from muscles) as a hydrostatic skelton for movement.

3) The coelom helps enable the internal organs to grow and move independently of the outer 
body wall. Imagine if you could see the peristaltic action of your intestines if you did not have a 
body cavity! Ick! Basically, if the internal organs were not separated from the outer body surface 
you'd have a tough time moving and bending your body. This is because any movement by your 
external body would then distort your internal organs, perhaps causing problems. 

-Hope this helps!
-Mike

References:

Campbell & Reece (2002) 'Biology (6th Edition)" Benjamin Cummings, San Fransico. Page 638

Kingdom Animalia:
 http://www.lander.edu/rsfox/112anim.html