a) At the end of the story is a missing scene which appears to be well known to the public as the cocoon scene, in which Ripley finds Captain Dallas spun into a web in the hold of the Earthship, Brett and (and at one time) Parker have also been spun into cocoons which are in the process of metamorphosing into the very same type of egg found in the pyramid, thus completing the Alien's life cycle (Dan O'Bannon's Unseen Alien, Starburst 15, p42) .
b) The first containing Dallas appears to be woven from some fine, white, silk-like material, and it is slowly undulating. Another cocoon dangles from the ceiling, but this one looks a little different. It is smaller and darker, with a harder shell. In fact, it looks almost exactly like the spores in the tomb thus completing the Alien Life Cycle (Dan O'Bannon's online early Alien script.)