Dinosaur egg size (usually not much longer than a centimeter or two) and lack of an eggshell with its typical anatomy. Stones: The erosive effects of water can sometimes round rocks into egg-like shapes. Paleontologists' knowledge of the structure of dinosaur eggs is limited to the hard shell. However, it can be inferred that dinosaur eggs had an amnion, chorion, and an allantois, the three major membranes in modern bird and reptile eggs. Dinosaur eggs vary greatly in size and shape, but even the largest dinosaur eggs ("Megaloolithus") are smaller than the largest known bird eggs, which were laid by the extinct
Specimens of Archaeopteryx Tischlinger & Unwin (2004), who reclassified it as part of the sternum, albeit minimally ossified (mostly cartilagenous). This supports the idea that the Berlin "Archaeopteryx" was not a full-grown individual at the time of its death, and instead represents an immature animal. The pelvis of the Berlin specimen was considered by Dames to be markedly different from that of the London specimen, which was a major point in favor of his assigning a new species to the Berlin "Archaeopteryx", "siemensii", after its generous donor. Other researchers, however, disputed this difference, claiming it could be entirely accounted for by deformation of