Polyps and sclerites of Narella enigma from the holotype, JSL-I-1915, USNM 1409703. a lateral stereo view of a whorl b–c abaxial and adaxial stereo views of a polyp, respectively d articular ridge and inner ridging on a basal spine e basal scales f medial scale g buccal scales h opercular scales i coenenchymal scales, in situ j coenenchymal scales.