The test is subcircular and has short and reasonably narrow naked median interambulacral regions that have undulating edges. These are lilac, with each median region having an undulating purple line that starts from the genital plate and continues down the inetrambulacra, but stops above ambitus. These naked median regions have red borders that do not continue beyond the naked region. Primary spines are only slightly curved and unbanded. These are red distally (on the dorsal surface) blending into green proximally, while the spine's collar is brown. The collar has has two small longitudinal ridges either side of the central dorsal ridge, with many ridges on the ventral surface, but no granules between ridges. Secondary spines are pointed, tapering distally. Ophicephalous pedicellariae are abundant both orally and aborally. These have unconstricted valves, with distal and proximal regions of equal length.
This species is similar to C. undulatus and C. maculatus in having narrow and short naked median regions on its interambulcra. It is also similar to C. undulatus in the colouration of the primary spines. However, it differs from these species in having pointed secondary spines and aboral ophicephalous pedicellariae with unconstricted valves (club-shaped secondary spines and aboral ophicephalous pedicellariae with moderately constricted valves in both C. undulatus and C. maculates. The pattern on the naked median regions of the interambulacra is similar to C. longicollis and C. granulatus, however, these naked regions are greatly reduced in size in C. australis.
Thought to be endemic to Australia