Funny thing though... Snakes do have an umbilical of sorts attached within the egg.

Which reminds me of a very UNfunny incident I had years ago, when a hatchling corn snake of mine (I hate this word...) ahem! disemboweled (always icky) itself because its umbilicus stuck to the plastic of the container the eggs were in....
and it apparently kept tugging to get away. When I noticed this, it was already too late. It was a rather traumatic experience for me.
Soooo. .. just in case you're incubating, try to always add some extra incubation substrate up along the walls of the container....

Steve