Colochirus

Troschel, 1846

8 species

Body mostly 4 cornered. Anterior and posterior ends curved slightly upwards. Radii on the edge of the skin and in the introvert as well have skin growths. The feet are piled on the middle section of the ventral radii. On the anterior and middle portion of the ventral radii there are papillae instead of feet. In the dorsal radii as well as in the dorsal interradii, the papillae are less numerous. They are mostly on warts. There are 10 tentacles, the two ventral ones smaller. The calcareous ring is simple, without forked tail. In the upper skin there are cups, below that knobbed plates and many layered scales which usually cover each other roof tile fashion. (Panning, 1949)

The body is spindle shaped to 4 edged. The mouth has 4 flaps. The radii are with or without growths. Ventral there are feet in the radii; dorsal the radii have feet or papillae, the dorsal interradii are naked or have papillae. There are calcareous deposits in 4 forms: to the surface there are cups or bowls. Between and below the cups there are, as a second form, delicate broken hollow deposits without any inner support. They are usually a bit larger than the cups. Below these there lie, as a third form, hollow deposits with an inner support framework, consisting of a middle plate with a cover plate on each side which is connected to the inner plate by rod supports. As a fourth form, there follow large scales of several layers of network. The large hollow deposits mentioned in the 3rd place lie as a third layer over the scales or else between and below them. (Panning, 1971)