This is a 4ft adult male:
http://www.corallus.com/cenchria/crassus001.jpg
http://www.corallus.com/cenchria/crassus002.jpg
This is one of the larger Rainbow Boa species having uniform large circles dorsally but little patterning elsewhere.
They can be kept in 30gallon+ plastic rubbermaids (10-20$ at home depot) and should be heated with heat pads (25-35$ at Reptilia, or 16-20$ at Zellers). Day time temps should be 85F, with a hot spot of 90F. Night time temps should be 76-79F.
Relative humidity between 50-70%, but a little higher when going into shed. This can be achieved by spraying often, or placing the large water dish over the heatpad. It is best to keep these in platic rubbermaids, or cutsom wood/plexi glass enclosure because it is a lot easier to control humidity.
These snakes are primarily terrestrial, but will benifit from a few strong branches. Best substrate is mulch, as they like to burrow, but they will also do well on old newspaper or paper towel.
A hidebox is require, a large, upside down plant pot with a hole cut in the side or top will do vert well. Relative humidity in the hide should be higher (60-80%) than in the rest of the enclosure.
If you have any more Qs let me know :]
*Note, the correct spelling is paraguAyan, which may explain any lack of results when searching for them online :]