In the Coal Measures they commonly occur in the underclay beneath the coal-seams. Complete specimens of the stumps show that from the base of the aerial stem four Stigmarian branches were given off, which took a horizontal or obliquely descending course, forking at least twice.
- Diagram of a simple form of Crinoid, with five arms, each forking once; the one nearest the observer is removed to expose the tegmen of five orals.
- Antlers flattened or rounded, without bezor trez-tine, the beam dichotomously forking, and one or both branches again forked, so that the number of tines is at least four; brow-tine forming a right angle or a continuous curve with the beam; coat of adult generally more or less uniform, of young spotted.
- Lateral metacarpals as in Rangifer; antlers rather small, without a brow-tine or sub-basal snag, dichotomously forked, with the upper or posterior prong again forking; tail rudimentary; vomer not dividing posterior nasal aperture of skull.
Cristatum is a handsome variety with fronds forking at the apex and the tips of all the pinnae crested and curled.