 The glabella was inflated, and globular-shaped, and covered in small wart-like bumps.If it was filled with fat, or oil, the glabellum would have helped to have made the creature positively buoyant.On the other hand, trilobites with large glabellae are often suspected of being predatory, as the volume of glabella would be filled with digestive organs, or used to store captured/swallowed prey.