a) It would seem as if Giger took notice of the Land That Time Forgot poster, perhaps finding inspiration in the extreme liberties that the poster artist took which bear little likeness to what's seen in the film
|Giger's Mordor VI (work 282) (1975)|
b) Manta ray type creature becomes absorbed into the head of this monstrosity. It's laser beam becomes the tongue.
c) Elements of the the submarine becomes absorbed into the Bishop Fish character.
The minisub in this instance becomes the round buttocks like forms that the hand rests upon, and the octopus head becomes multiplied as a row of suction cups for milking.
d) Rows of Tyrannosaurus teeth and their equivalent as a ribbed column on the body of the character in the background on the left.