Fig. 11
Lytechinus williamsi Chesher, USNM E14894, SE micrographs of broken sections through primary spines. a Stub C7, distal end of spine. b Stub C7 (different specimen from a, f), broken end of spine. c Stub C8, broken end of long spine. d Stub C9, broken end of spine. e Stub C8 (different specimen from c, g), broken end of spine. f Stub C7 (different specimen from a, b), broken end of spine. g Stub C8 (different specimen from c, e), broken end of spine. All scale bars represent 200Â ÎĽm