During the preparation and arrangement of a series of Lovenia forbesi from the Australian Miocene (presented to the Geological Department by Professor F. J. Cole), a peculiar interambulacral structure was displayed. Two of the specimens are severely weathered, with the result that their surfaces are smooth (except for the areolæ of the large tubercles), while the sutures are clearly outlined in dark brown across the pale background of the plates. In this way there is revealed the surprising fact that plate-crushing and resorption, of a type similar to that often found in Echinoid ambulacra, occur in four of the interambulacral areas. There is no corresponding development in the ambulacra.