4D Vision has introduced a host of animal models based on their anatomical structure. Each model has removable bones and organs and includes an illustrated assembly guide describing each of the bones and organs you remove. The guide also shows you how to put the whole thing back together.
4D Vision made a wide array of models including, but not limited to, a crocodile, shark, cow, horse, pig, dolphin, dog and even dinosaurs like the T-rex and triceratops -- all of which would be perfect for a science classroom, anatomy geeks or kids who just like taking animals apart (as long as they're old enough not to swallow the pieces.)
Give a couple of these models to your kids and they'll gain a greater understanding of anatomy at an early age -- or they'll use them to create gruesome hunting scenes with organs and bones everywhere; either way, these are cool toys.