by William Swainson

“ Those higher naturalists, who have long since abandoned the belief in absolute divisions and isolated genera, are fully aware that no groups are more likely to exhibit the arrangement of nature, than such as contain numerous species, under a great diversity of forms. ”

“ In general habit it has a close affinity to the first, but is distinguished by intermediate false varices, which in that species are wanting; while the upper and lower spines are alone vaulted: from Imperialis our shell is further removed, by the varices being spinous, instead of nodulous ”