(Eaton, Ohio, U.S.A)
I have recently read the Percy Jackson and The Olympians series, and in the last book Typhon was mwntioned as being a Titan. None of the informaion of him having one hundred heads, or snakes around his thighs was mentioned. He was described as human looking, but much other information and pictures i have found, show him in your description, with snakes in stead of legs and only one head, or with wings. also, the monster Chimera has been show with a dragon head as well. I belive this is just people getting information from different sorces, but i would like to inform you.
The Percy Jackson series is not an accurate representaiton of Greek gods and goddesses, it is a transposition in modern life of these characters. Something like: if they lived now, how would they look like? The books are also a great introduction to Greek mythology, i.e. they make you aware that there was a god called X Y Z, but if you want to know more about the real Greek mythology, you have to look for info on your own... and you can find some on it on this site ;-)