[14] ὄπισθεν, behind.
[15] Pulmo, a lung.
[16] στὕλος, pillar; ὄμματα, eyes.
[17] The Ascoglossa are dealt with below (chap. xv.).
[18] Beudant, by very gradually changing the water, accustomed marine species to live in fresh, and fresh-water species to live in salt water.
[19] Braun, Arch. f. Naturk. Liv. (2), x. p. 102 f.
[20] Lindström, Oef. K. Vet. Förh. Stockh., 1855, p. 49.
[21] Mendthal, Schr. Ges. Königsb., xxx. p. 27.
[22] SB. K. Akad. Wiss. Wien, 1889, p. 4, but the view is not universally accepted.
[23] Not to Nassa, as has been generally held. The shape of the operculum, and particularly the teeth of the radula, show a much closer connexion with Cominella.