Saturday, April 21, 2012

Hederella Bryozoan

These pictures were taken using a microscope and are of bryozoan growing on crinoid stems. Fossils are from the Mississippian Period. They were found in the Glen Dean formation of Grayson County, Kentucky.

The byrozoan appears to be a Hederella sp. I believe these were named by Ray S. Bassler in a paper entitled The Hederelloidea a suborder of Paleozoic cyclostomatous Bryozoa (1939, Smithsonian Institution). He defined the genus as:
Zoarium attached to various foreign organic objects and rarely to pebbles or other inorganic substances, branching, consisting of a tubular axis composed of the earlier part of successive zooecia from which the zooecia bud laterally, alternately to right and left; tubes annulated transversely but finely striated longitudinally; apertures terminal, transversely-elliptical.