Spermosoma grimaldii Koehler, 1897. Recent.
Drawings of aboral ambulacral plating and apical disc. From
Mortensen, T. 1935. A monograph of the Echinoidea. Volume 2,
Bothriocidaroida, Melonechinoida, Lepidocentroida and
Stirodonta. C.A. Reitzel, Copenhagen (Figs 107,