1 Autozooids retractile within short, hemispherical cortical mounds; long spindles in the tentacles absent... 2 (Fig. 2, 5 A, 8 A)
- Autozooids contractile, forming prominent cylinders when contracted; long spindles in the tentacles present.. 5 (Fig. 10 A, B)
2 Cortical mounds distributed on all sides of the colony; double clubs absent in cortex; live colonies with cortex and axis usually red.......................................................................................... C. rubrum
- Cortical mounds distributed predominantly on one side of the colony; double clubs abundant in cortex; live colonies with cortex white, yellow or pinkish; axis yellowish or white.......................................................... 3
3 Elongated 8 -radiates (Fig. 9 Ae, Be; higher than 0.1 mm) in both cortex and cortical mounds present; double clubs wider than high (0.027 × 0.034 – 0.041 × 0.064 mm)................................................. C. johnsoni (Fig. 8, 9)
- Elongated 8 -radiates in both cortex and cortical mounds absent................................................. 4
4 Cortical mounds with eight obvious lobes extending to the base; regular double clubs without apparent lateral projections; double clubs (0.042 × 0.048 – 0.074 × 0.078 mm) with similar width and height, cortex yellow or white; phylogenetically classified in Clade IA......................................................................... C. medea (Fig. 5)
- Cortical mounds without eight obvious lobes extending to the base; regular double clubs mostly with apparent lateral projections; double clubs (0.040 × 0.043 – 0.057 × 0.064 mm) with more prolonged and closer heads; live colonies with cortex pinkish, yellowish in ethanol; phylogenetically classified in Clade II......................... C. occultum n. sp. (Fig. 2 –4 A)
5 Double clubs not present or rare.......................................................................... 6
- Double clubs abundant................................................................................. 7
6 Eight-radiates predominate, 6 - and 7 -radiates common; elongated and symmetrical 8 -radiates present; live colonies with white to lightly pink cortex, snow white axis....................................................... C. niobe (Fig. 7 C)
- Six-, 7 -, and 8 -radiates predominate; elongated and symmetrical 8 -radiates absent; live colonies with deep pink to red cortex, red axis................................................................................. C. bathyrubrum
7 Heads of double clubs smooth with weak protuberances; branching in one plane extremely profuse; live colonies with ochraceous yellow cortex and orange autozooids....................................................... C. maderense
- Heads of double clubs rough with obvious protuberances; branching in one plane moderately dense; live colonies otherwise coloured............................................................................................ 8
8 Double clubs large, with two jagged-edged heads decorated by hypertrophied rays or pointed projections; live colonies white with slightly pinkish autozooids......................................................... C. bayeri (Fig. 7 A, B)
- Double clubs small, with two not well separated heads decorated by blunt projections; live colonies yellow to cream with vermilion red or pink autozooids............................................................ C. tricolor (Fig. 10)