Toxopneustidae


All Camarodonts have imperforate tubercles and compound ambulacral plates. In addition, the Toxopneustids are characterised by the peristome, or opening through the test, having a sharp margin with the buccal notches being prominent. The tubercles lack the crenulations or ring of cog-like structures that articulate with the spines in certain other families. The Aristotle's lantern, or jaw apparatus, has the keeled teeth and the epiphyses united above the foramen magnum, the V-shaped gap between the hemipyramids that support the lantern's tooth.[2]