Note 2217 — BOOK IX. THE NATURAL HISTORY OF FISHES.

“Rotæ.” Cuvier suggests that this idea of the wheel was taken from the class of zoophytes named “Medusæ,” by Linnæus, which have the form of a disc, divided by radii, and dots which may have been taken for eyes. But then, as he says, there are none of them of an excessive size, as Pliny would seem to indicate by placing them in this Chapter, and which Ælian has absolutely attributed to them in B. xiii. c. 20. Of the largest rhizostoma, Cuvier says, that he had even seen, the diameter of the disc did not exceed two feet.