Oh my, now this is a very cool item! Everybody loves the Tyrannosaurus Rex, the "king of the dinosaurs," but just how well do we really know the king? Sure, we're all familiar with the bones and the outer appearance, but now here's an excellent chance to get to know this master of prehistoric predatory mayhem from the very inside out! Yes, this "4D Vision" T-Rex anatomy model, touted as a "new type of puzzle," takes us on a harrowing journey through the inner workings of this mighty monster, including all the major internal organs, muscle groups, and of course the bones and external features. Beautifully crafted in 39 parts, the internal bits can be removed and replaced, with the entire left side of the beast molded in clear plastic to reveal all the goodies inside! It should be noted that since the only remains of T-Rex ever found were fossil bones, the internal organ arrangement is of course a bit conjectural...but the cooperation of international authority in vertebrate paleontology and paleoanthropology Dong Zhi Ming means that this model is probably as close to reality as it could be. Includes an illustrated guidebook (in Japanese). A great learning tool for all fans of paleontology, or of Steven Spielberg!