This trepostome bryozoan shows the typical pattern
of bioerosion in the Paleozoic. The small holes are the cylindrical
"worm" boring Trypanites; the larger holes are
bivalve borings known as Petroxestes. The scale bar is
in millimeters; the specimen is from the Whitewater Formation,
Upper Ordovician, near Richmond, Indiana. (Next Trypanites.)
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