Fig. 10

Lytechinus variegatus (Lamarck), USNM 3088, SE micrographs of broken sections through primary spines. a Stub C4, broken end of spine. b Stub C5, broken end of spine. c Stub C4 (different specimen from a, d), broken end of base of large spine. d Stub C4 (different specimen from a, c), broken end of small spine (secondary?). e Stub C5 (different specimen from b), broken end of spine. f Stub C6, broken end of long spine. All scale bars represent 500 μm