. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. CEPHALOPODA. 531 ascertaining if these muscles presented a corre- sponding degree of development, but found them proportionally smaller even than in the naked Octopus. All trace of internal shell has disappeared in the Ocythoe; yet there is no muscular connexion between the body and the external shell which contains it. The fleshy fibres of the mantle being white like the rest of the muscles, and very compact, are extremely difficult to follow in dissection. Cuvier* observes, that in the Octopus those which are external
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. CEPHALOPODA. 531 ascertaining if these muscles presented a corre- sponding degree of development, but found them proportionally smaller even than in the naked Octopus. All trace of internal shell has disappeared in the Ocythoe; yet there is no muscular connexion between the body and the external shell which contains it. The fleshy fibres of the mantle being white like the rest of the muscles, and very compact, are extremely difficult to follow in dissection. Cuvier* observes, that in the Octopus those which are external are evidently longitudinal; those which are internal, transverse; and that there are short fibres which pass through their thickness from one surface to another. In the Cuttle-fish the muscular fibres of the posterior part of the mantle recede laterally to leave a large space for the lodgement of the sepium or cuttle-bone, which is covered exter- nally by a thin and flaccid skin : the rest of the mantle is formed by a thick muscular tissue, as in the Poulp. The lateral fins are connected not only by the skin, cellular tissue, and vessels, as Cuvier describes, but by a distinct though thin stratum of muscular fibres; these arise from the lateral and dorsal aspects of the apo- neurotic capsule of the rudimental shell, and are inserted into the spinal rid^e of the alar cartilage (h, h, Jig. 212) ; from this ridge pro- ceed the fibro-cartilaginous laminae and inter- mediate muscles, which are disposed perpen- dicularly to the ridge, and extend to the mar- gins of the fin. In the Calamaries the muscles which con- nect the terminal fins to the body are still more distinct. By means of these fins they are enabled to propel themselves forward in the sea; and there is good reason for believing that some of the small slender-bodied subu- late species of this genus are enabled to strike the water with such force as to raise them- selves above the surface, and dart, like the flying fish,
Size: 1717px × 1456px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bo, booksubjectanatomy, booksubjectphysiology, booksubjectzoology
