The Echinoid Directory

1a. Areoles of primary tubercles with radial pits; primary spines with long, tuberculate collar.

1b. Areoles of primary tubercles hardly sunken and without radial pits; primary spines without long collar.

2a. Primary spines with irregular pustular ornamentation on shaft.

2b. Primary spines with coarse spinules along shaft.

3a. Adoral ambulacral plates with enlarged primary tubercle on every second plate. Scrobicular tubercles hardly differentiated.

3b. Adoral ambulacral plates uniform without enlarged primary tubercle on every second plate. Ring of scrobicular tubercles differentiated.