It is unlike both the original Zeppelins that had a rigid skeleton and non-rigid blimps.

He looks more like a dirigible, but he's not, because he doesn't have a rigid skeleton.

The most important feature of Zeppelin's design was a rigid light-alloy skeleton, made of rings and longitudinal girders.

Each sponge in the order Hexactinosa has a rigid skeleton that persists after the death of the animal.

Joints hold your bones together and allow your rigid skeleton to move.

The spicules may be only loosely associated within the sponge tissues, or may be more or less fused to form rigid skeletons.

All sand dollars have a rigid skeleton known as a test.

Sand dollars, like all members of the order Clypeasteroida, possess a rigid skeleton known as a test.

The most distinctive feature of cystoids was the presence of a number of pores in the rigid skeleton encasing the body.

They have relatively weak wing muscles, and their thoracic cuticle plates are not fused together to create a rigid external skeleton.