Arachnoides is a genus of sea urchin within the family Clypeasteridae, found in the Indo-Pacific oceans. The base is flat and the upper surface is convex.
Species The World Register of Marine Species list the following species as being in this genus:-
Arachnoides placenta (Linnaeus, 1758) Australia to Philippines Arachnoides tenuis H. L. Clark, 1938 Western Australia
Arachnoides zelandiae Gray, 1855 New Zealand: Synonym of Fellaster zelandiae (Gray, 1855)
References
Natural History Museum