Lectures on the comparative anatomy and physiology of the invertebrate animals : delivered at the Royal College of Surgeons . , fixed to the walls of the cell by four muscular fasciculi: fourother bundles attach the opercular ring to the border of the openingof the cell: the movements of this muscular mechanism are bothcurious and beautiful when the little polype protrudes from or drawsback into its ceU. In the cylindrical Bryozoa, as the Boiverhankia, the flexible partof the integument consists of two portions ; the lower half being asimple continuation of the cell; the upper one consisting o
Lectures on the comparative anatomy and physiology of the invertebrate animals : delivered at the Royal College of Surgeons . , fixed to the walls of the cell by four muscular fasciculi: fourother bundles attach the opercular ring to the border of the openingof the cell: the movements of this muscular mechanism are bothcurious and beautiful when the little polype protrudes from or drawsback into its ceU. In the cylindrical Bryozoa, as the Boiverhankia, the flexible partof the integument consists of two portions ; the lower half being asimple continuation of the cell; the upper one consisting of a cylin-drical series of setce {h), connected together by an extremely delicateand elastic membrane, permitting a certain extension of the cylinder,which, at the same time, supports and allows free motion to the upperpart of the body in its expanded state. The mouth of the polype issituated at this extremity of the body, and is surrounded by aradiated series of slender, ciliated tentacula (c), eight, ten, twelve, ormore in number, according to the genus. The muscular system is developed in the present highly organised. * CXXVII. p. 25. pi. i. fig. 1. e and BliYOZOA. 147 class of polypes, in the form of distinct groups of fibres. Theirarrangement, and the actions by which they effect the protrusion andretraction of the polype, are minutely and clearly described by * The retractor muscles form two series, one acting upon thealimentary canal, and the other upon the flexible part of the series rises from the bottom of the cell, and is inserted about thebase of the stomach {d) ; the other {e, B) arises from the oppositeside of the bottom of the cell, and passes upwards to be inserted nearthe base of the tentacula. The muscles which retract the flexibleintegument and the setose operculum arise near the upper margin ofthe cell (between e and a, B), and are disposed in six fasciculi, threeof which act upon the membrane, and the other three upon thebundle of seta3 by
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Keywords: ., bookauthorowenrichard18041892, bookcentury1800, bookdecade1850
