Diplocrininae with bowl-shaped cup. Basals rather small, separated on surface of cup. Arms divided at primibrachial ... [details]
Isselicrinidae with brachitaxes typically with fewer than 5 brachials beyond secundaxil (more in Cenocrinus). ... [details]
Isocrininae with 10 arms. Symmorphy between secundibrachials 3 and 4 and more distally. [details]
Articulata with cup cryptodicyclic, wider than high, low cone- or bowl-shaped; radial cavity wide, cup elements not ... [details]
Isocrinida with arms long, slender, branching mostly isotomous. Facets of brachials with well-developed muscle ... [details]
Isocrinida with arms long, slender; branching mostly isotomous. Facets of brachials with well-developed muscle ... [details]
Isocrinus with straight cryptosyzygy between secundibrachials 3-4. Internodes long, with as many as 20 columnals. [details]
Isocrinina with cryptosyzygy between primibrachials 1-2 and secundibrachials 1-2; in Metacrininae muscular ... [details]
Isocrinidae with base of crown conical, 10 arms in N. naresianus or more than 10 arms in N. blakei and N. ... [details]
Metacrininae with typically 4 primibrachials (range 3-6); only primibrachials 1-2 united by cryptosyzygy. [details]
Cainocrinidae with arms divided at primibrachial 2 and further divided at variable intervals of 1-6 brachials. ... [details]
"Subdividing the Isocrinida has been highly controversial. Bourseau and Roux (1989) and Bourseau and others (1991) ... [details]