Plexauridae Gray 1859

1. Sclerites of colonies include warty stellate plates with a central knob (Figure 20a,b) as well as cup-shaped rosettes (Figure 20c) in outer coenenchyme, with concavity of cup facing away from axis................................................... 2

- Sclerites of colonies include spindles (Figure 21 a-c), rods or thorn-scales (Figure 21d,e) but no cup-shaped rosettes in outer coenenchyme................................................................................................................................................... 3

2. Colony stout and branching, with branches and stems up to 3 mm thick; polyps closely set and numerous............... ................................................................................................................................. Bebryce cinerea Deichmann, 1936

- Colony slender, unbranched or sparsely branched; stem diameter not exceeding 1 mm; polyps widely set apart and sparse.............................................................................................................. Bebryce parastellata Deichmann, 1936

3. Sclerites of colonies include calicular thorn-scales........................................................................... Paramuricea sp.

- Thorn-scales absent...................................................................................................................................................... 4

4. Colonies with prominent conical calyces along two sides of branches, with large spindles (up to 3 mm) in coenenchyme and smaller spindles towards rim of calyces ...... Scleracis guadalupensis (Duchassaing & Michelotti, 1860)

- Colonies with crowded shelf- or dome-like calyces scattered on all sides of branches, largest sclerites not reaching 3 mm............................................................................................................................................................................... 5

5. Calyces appearing spiny or shelf-like (Figure 12l); calyx with large (often> 1 mm) orange spindles extending beyond its edge and very apparent when polyp is retracted. Coenenchyme containing spindles only............................................................................................................................................................... Muricea pendula Verrill, 1864

- Calyces domelike with no large sclerites. Coenenchyme with small colorless spindles, double heads, double cones (but see exception in Remarks on species).................................................................. Thesea nivea Deichmann 1936