[2581] The Echinus cidaris of Linnæus; with a small body, and very long spines. The name, according to Hardouin, is from the Greek, meaning the “mother of the echini.”
[2582] See B. iv. c. 17.
[2583] The same, Cuvier says, with the Echinus spatagus of Linnæus.
[2584] Not “ova,” Cuvier says, but “ovaria” rather. Each urchin has five “ovaria,” arranged in the form of stars. They are supposed to be hermaphroditical, but there is considerable doubt on the subject.
[2585] The mouth of the sea-urchin, armed with five teeth, is generally turned to the ground, Cuvier says.
[2586] Plutarch, in his Book “on the Instincts of Animals,” Oppian, Halieut. B. ii. l. 225, and Ælian, Hist. Anim. B. vii. c. 44, all mention this.
[2587] This idea probably arose from the fact of their being sometimes found with stones sticking between their spines or prickles.
[2588] The thin-crusted animals.
[2589] Known to us as periwinkles.
[2590] It is now known, thanks to the research of Swammerdam, that the black points at the extremity of the great horns of the land snail, or Helix terrestris, and at the base of them in the water snail, are eyes.