Sorry for the double post...
Chamber with the hole looked like a cargo hold to Dallas. They find an odd urn shaped thing, different material than ship(egg). It has a broken or jagged top.
Thought hole was an access shaft, no ladder or hand holds. smooth wall all the way down.
No other doors or opening in the "Cargo Hold" rigid walls, looks like the inside of a whale, ie the ribs.
Dallas thought hole was a regular part of the ship, given the even regular sides. considered explosion, but sides are to smooth.
Kane notices heat comming from below, suit reading says Kane is below ground level, shaft had the same surface all the way down, Kane confirms that this is another chamber on the ship.
Kane thinks it is a cargo hold, with bare walls and high ceilings. This cargo hold has "sott, flexibe look" opposed the the solid bone ribs.
On closer look, Kane can see that the stuff on the walls is not part of the ship, looks organic.
Kane is sure he is in a storage area. Finds the same urn like objects, looks like the Urn's are being stored in the Lower chamber. Looks to be arranged to somebody's concept of order.
There you go, that's what the novelization says about the ship and the aliens on board.
I would say the Aliens Homeworld is not LV-426.
