The Echinoid Directory

1a. One or more fascioles (partial or complete - indicated in yellow) present in adults.

1b. No trace of fascioles present in adults (but may be present in juveniles).

2a. Fasciole (marginal or subanal) crosses interambulacral plates 5.a.4 and 5.b.4 beneath the periproct.

2b. No fasciole beneath the periproct in the posterior interambulacrum crossing plates 5.4. (A fasciole band crosses above the periproct above plate 5.8).

3a. Fasciole forms a complete ring beneath the periproct (subanal fasciole).

3b. Fasciole extends around ambitus and crosses the lateral interambulacral zones (marginal/ lateroanal fasciole).

4a.Apical disc ethmophract.

4b. Apical disc ethmolytic.

5a. Sternal plates asymmetric; labral plate not contacting plate 5.a.2.

Somaliasteridae (part)

5b. Sternal plates symmetrical; labral plate in contact with both sternal plates.