. A manual of zoology. 3°4 MANUAL OF ZOOLOGY surface, which contract and expand under nervous influence (Fig. 189). On the postero-ventral aspect of the body the mantle encloses a wide cavity, the mantle-cavity (Figs. 190, 191), in which the ctenidia are lodged, and on the wall of which are situated the anal, excretory, and reproductive apertures. The mantle-cavity communicates at its oral end by a wide slit with the exterior; but this is capable of being closed, Fig. 189. —Chromatophore c-t* Sepia, magnified, nuc, nuclei in wall of sac; pigm, pigment; rad. 71171s, vadiating strands
. A manual of zoology. 3°4 MANUAL OF ZOOLOGY surface, which contract and expand under nervous influence (Fig. 189). On the postero-ventral aspect of the body the mantle encloses a wide cavity, the mantle-cavity (Figs. 190, 191), in which the ctenidia are lodged, and on the wall of which are situated the anal, excretory, and reproductive apertures. The mantle-cavity communicates at its oral end by a wide slit with the exterior; but this is capable of being closed, Fig. 189. —Chromatophore c-t* Sepia, magnified, nuc, nuclei in wall of sac; pigm, pigment; rad. 71171s, vadiating strands of muscle. (After Vogt and Jung.) so that, when the walls of the cavity contract, a stream of water is ejected through the funnel, and the animal is propelled in the aboral direction. Swimming is also effected in the Dibranchiata by means of a pair of fins in the shape of muscular, lateral flaps. The ctenidia (cteri) are plume- like, and are either two {Dibranchiata) or four {Tetra- branchiata) in number. The mouth is provided with a pair of horny or calcified jaws (Fig. 192, B) similar in shape to the jaws of a parrot. The buccal cavity contains an odontophore. Opening into. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Parker, T. Jeffery (Thomas Jeffery), 1850-1897; Haswell, William A. (William Aitcheson), 1854-1925. New York, The Macmillan Company; London, Macmillan & Co. ,Ltd.
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Keywords: ., bookcentury1900, bookdecade1900, bookpublishernewyo, bookyear1900
