Archive image from page 458 of The cyclopædia of anatomy and. The cyclopædia of anatomy and physiology cyclopdiaofana03todd Year: 1847 445 \l Leptopus longipes. the centre of gravity c backwards in the direction of d e, but by the elongation of one set of legs from J to h, and subsequent re- traction towards _/', and the simultaneous con- traction of the other set from f to h', and subsequent extension towards/', the centre r v.'ill be propelled laterally in the direction of a l>, perpendicular to d e. The lines a b, d e represent both the magnitude and direction resulting from the two
Archive image from page 458 of The cyclopædia of anatomy and. The cyclopædia of anatomy and physiology cyclopdiaofana03todd Year: 1847 445 \l Leptopus longipes. the centre of gravity c backwards in the direction of d e, but by the elongation of one set of legs from J to h, and subsequent re- traction towards _/', and the simultaneous con- traction of the other set from f to h', and subsequent extension towards/', the centre r v.'ill be propelled laterally in the direction of a l>, perpendicular to d e. The lines a b, d e represent both the magnitude and direction resulting from the two movements of the legs, in g f, g' f and /; f, h'Jf respectively, but, by changing the position of the legs, they may also move obliquely. The Macrourous Decapods, as the lobsters, are all organized for swimming ; and they have accordingly been considered under that section. Gasteropoda.—The motions of the Gastero- poda are proverbially slow; the situation and structure of the muscular foot enable them to traverse surfaces vertically, as well as horizon- tally. The centre of gravity is supported within the base formed by the disc of the foot, which is organised to expand, contract, and curve in every direction; also to produce a vacuum, and to secrete an adhesive fluid for the pur- pose of securing the stability of their position on surfaces direc'ed at any degree of obliquity, or on the ceilings of rooms, or roofs of buildings, in opposition to the force of gravity. The Limaces, or slugs, and Helices, snails, present in progression a crawling or gliding motion. When, for instance, the Heliv poniatia prepares for moving, the head, neck, and foot are first protruded from the shell; the foot is next extended on the plane of position, with the shell raised upon it; the muscular fibres of the foot then produce an alternate contraction and elongation of the successive segments of its disc, commencing posteriorly and proceed- ing forwards by a visible undulatory motion. During the
Size: 1716px × 1165px
Photo credit: © Actep Burstov / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: 1840, 1847, anatomy, archive, book, bookauthor, bookdecade, bookpublisher, booksponsor, booksubject, bookyear, drawing, historical, history, illustration, image, london_sherwood_gilbert_and_piper, mblwhoi_library, page, physiology, picture, print, reference, todd_robert_bentley_1809_1860, vintage, zimmermann_a_albrecht_b_1860, zoology
