The Echinoid Directory

• Home
• Introduction
• Morphology
• Keys
• Classification
• 3D models
• Index to taxa
• Glossary
• Log in

Key to the genera of Palaeostominae

12a. Episternal plates biserially arranged. Go to 13	12b. Episternal plates strongly offset and almost uniserial. Palaeostoma
13a. Petals and frontal ambulacrum long, narrow and parallel-sided. Sarsiaster	13b. Petals strongly bowed, anterior ambulacrum well developed, with distinct frontal groove. Ditremaster