An attempt towards a natural history of the polype : in a letter to Martin Folkes / By Henry Baker.

  • Baker, Henry, 1698-1774.
Date:
1743
Catalogue details

Licence: Public Domain Mark

Credit: An attempt towards a natural history of the polype : in a letter to Martin Folkes / By Henry Baker. Source: Wellcome Collection.

    31/236 (page 25)
    Space that always remains tranfparent, even when byFullnefs, or Contraction, the other Parts are rendered quite opake: and in this Space the Microfcope difcovers a Kind of fluctuating Motion, very much like that in the Arms, wherewith it feems to commu¬ nicate. The outward Coat is white like the Arms, and made up of minute Annuli or Ringlets, that double in the midft, and can, occafionally, be folded clofe together, in the manner of a Paper Lanthorn. Thefe may plainly be feen, when the Body is in its mid¬ dle Degree of Extenfion: but when it is quite ftretched out, they become unfolded* and confequently not diftinguiffiable; and when quite contracted, are not perceivable, by their being brought too clofe. The Ap¬ pearance of them may be underftood by fome of the foregoing Draughts.—See the Figures, Page 12 and 14. Such a Structure accounts, in fome meafure, for that extraordinary Ability this Creature has, of fo extending or contracting every Part about it, that it is difficult, if not im- poffible, to afcertain the real Length or Thicknefs of any. It will eafily be conceived that the Thicknefs muft increafe as the Length diminifhes: for its Body is, probably, compofed of longitudinal, and circular, or perhaps fpiral Fibres, both capable of great Extenfion or Contraction 5 and which coun¬ teract, in fuch a Manner, that when one ex¬ tends.