Alien, I mean really Alien.

[Randallw]

Wow, did this thread take off. I bow to Captain Kwok and others superior knowledge, as I explained I am no expert I was simply trying to put forth some limited knowledge I had. So my numbers might be wrong but I seemed to remember it was a proportion such as 5 out of 20. It could well be 3 out of 15, but I'm pretty sure the number of fossils was less than 20 "types". The types I was referring to are (using my simple example)
1. creature with a backbone and 4 limbs.
2. creature without a backbone.
3. Creature with a backbone but 3 unsymetrical limbs spaced around torse (like Cygnans from Jupiter theft).
4. Creature with 20 legs and backbone (sort of like a centipede but not an insect).
5. creature with a tubular body and circular mouth studded by teeth in 3 sets (like a lamprey).
6-20 various other types.
basically think of 20 really alien variations on possible forms, but only (in my example) 5 survived.

I read this in a magazine many years ago and it stuck in my mind. The magazine could have been Popular Science, National Geographic or Time for all I know. I apologise for being unable to provide links or detailed information, really I was hoping for someone with more knowledge to elaborate on what I knew. For the person who wanted to know the 3 types of Monotremes, they are 1 type of Platypus and there are 2 type of Echidnas.