Siamese and Colorpoint Shorthairs both have the same body types with long tapering lines, very lithe but muscular. The head is a total wedge that starts at the nose and flares out in straight lines to the tips of the ears forming a triangle. Their necks, like their legs are long and slender. The paws are dainty, small, and oval and the tail is long and tapering to a fine point. The hair lies close to the body since they do not have an undercoat. Basically the main differences between the two breeds lie in the colors that they can be found in.
The Siamese are only found in four colors, the well known seal point, chocolate point, blue point and lilac point. They only allow these four colors within an eight generation pedigree. The Colorpoint Shorthairs may also be found in these colors but are considered AOV (any other variety). The preferred colors of the CPSH are the red point, cream point, parti-colors of the seal tortie, chocolate tortie, blue cream and lilac cream points. Then there are also the lynx points with blue, blue-cream, chocolate, chocolate tortie, cream, lilac, lilac-cream, red, seal, or seal-tortie.
For more information about these breeds you may read more on the Cat Fanciers Association website. www.CFA.org