Fig. 4 in The tube wall of Cambrian anabaritids

Fig. 4. Jacutiochrea tristicha (Missarzhevsky), specimen SMNH X3416, sample K2/25. A. Tube, with positions of B, D and E (arrow) indicated. B. Close−up of A, showing fractured apertural flange. C. Close−up of B, showing boundary between inner, fibrous, and outer, more solid, fabric. D. Close−up of A, showing hole after euhedral crystal penetrating the celestite−replaced wall. Picture light−dark inverted to make crystal habit more visible. E. Close−up of lower part of tube (slightly tilted from A), showing persistent celestite cleavage pattern oblique to axis of tube. F. Close−up of E, showing hole after euhedral crystal and celestite cleavage pattern.