Apex posteriorly sub-central.
Petals close, nearly symmetrical, the anterior and posterior ones the longest, as wide as or even wider than the inter-ambulacral spaces; ambulacral areas composed of very narrow plates, widening on the margin.
Inferior surface plane.
Ambulacral furrows not visible in the specimens examined.
Mouth small, central.
Anus very small, sub-marginal.
Papillary tubercles numerous, rounded, somewhat prominent, more crowded beneath than above.
| Length | 1.22 | inches. |
| Width | 1.06 | ” |
| Height | 0.30 | ” |
Locality: Two miles east of Walnut Creek House; from miocene beds.
Collection of the State Geological Survey, and mine.