[284] Journ. of Conch. vi. p. 349 ff.
[285] Quart. Journ. Micr. Sc. N.S. xv. p. 37.
[286] Ann. Mag. Nat. Hist. (2), xx. p. 336.
[287] V. Willem (Arch. Biol. ut infr.) denies this, and declares that Cyclostoma is only very sensitive to movements. The present writer has often approached, with the greatest care, a crawling Cyclostoma, but it always withdrew into its shell or fell to the ground when approached within about 10 or 12 inches.
[288] Arch. Biol. xii. 1892, p. 57.
[289] ‘Challenger’ Reports, Zoology, vol. xxvii. part lxxiv. p. 3.
[290] Animal Life, p. 372 f.
[291] Bergh, Morph. Jahrb. x. p. 172.
[292] Ann. Mag. Nat. Hist. (5) xiv. p. 141.
[293] The nature of the grouping of the eyes into rows varies considerably in different species. As a rule, the rows radiate from the beak, but occasionally they run parallel to the girdle. In Tonicia lineolata Fremb., they are grouped, as it were, under the shelter of strongly marked longitudinal wavy lines.