This variety differs from the typical form only in the shape of the hairs on the primary spines, these being ... [details]
Mortensen (1928b: p. 437, under the name C. circinnata), following A. Agassiz, tentatively considers this a junior ... [details]
The var. teretispina Döderl. appears to differ from the typical Alcocki (tricarinata) only in its primary spines ... [details]
Generic attribution tentative [details]