Proximal half of tail (right posterolateral), showing Ca1-14 and part of Ca15. The chevrons in this region at Y-shaped in anterior view, and simple in lateral view, except for a hint of an anteriorly-directed process on chevron 12/13, which may misplaced. (The spine behind the three fused sacral spines represents the posterior part of the sacrum, S4; the next vertebra behind that is Ca1, so that Ca3-4 appear to ``share'' a neural spine.)