Phylogeny of the Echini: With a Revision of Palaeozoic Species, Volume 2

ambitus ambulacral area Ambulacral detail ambulacral plates ambulacrum Archaeocidaris basicoronal row beveling brace Burlington CALIFORNIA columns of interambulacral columns of plates Comp Compare Plate Compare text-fig Cotypes demi Diam Dorsal view dorsally dotted lines Drawings enlarged epiphyses external F. A. SAUNDERSON five columns foramen magnum four columns glenoid cavity half-area half-pyramid HELIOTYPE HENRY BLAKE heptagon heptagonal plate HIST Holotype Hook Head indicated by dotted interambulacral area interambulacral plates internal mold interpyramidal muscles Keokuk Group lantern Limestone Lovenechinus Lower Carboniferous madreporite Meek and Worthen Melonechinus MEMOIRS BOSTON SOC mid-zone Museum Natural occluded plates Palaeozoic paratype pentagon peristome plate of column plates imbricate plates in area plates ventrally pore-pairs biserial primary spine pyramid R. T. J. Coll SAN DIEGO secondary tubercles showing six columns specimen as photograph spinules Springer Coll suture tubercles uniserial Univ UNIVERSITY LIBRARY ventrally W. M. Barrows Zoöl