. The crayfish : an introduction to the study of zoology . Crayfish. 100 THE PHYSIOLOGY OF THE COMMON CRAYFISH. and the thoracic part of the ner\-ous system; while, in the abdomen, its strands are attached to the sternal exoske- leton of all the somites and extend, on each side of the rectum, to the telson. When the exoskeleton is cleaned by maceration, the f-"^ irum XM ^X'^ ^ I XK. Fig 22.—Astacvs flmiatUis.—A longitudinal section of the body to show the principal muscles and their relations to the exoskeleton (nat. size), a, the vent; , adductor muscle of mandible ; cm, exten
. The crayfish : an introduction to the study of zoology . Crayfish. 100 THE PHYSIOLOGY OF THE COMMON CRAYFISH. and the thoracic part of the ner\-ous system; while, in the abdomen, its strands are attached to the sternal exoske- leton of all the somites and extend, on each side of the rectum, to the telson. When the exoskeleton is cleaned by maceration, the f-"^ irum XM ^X'^ ^ I XK. Fig 22.—Astacvs flmiatUis.—A longitudinal section of the body to show the principal muscles and their relations to the exoskeleton (nat. size), a, the vent; , adductor muscle of mandible ; cm, extensor, and^.w/, flexor muscle of abdomen ; tes, cesophagus ; pep, procephalic process ; t,f, the two segments of the telson; XV—XX, the abdominal somites ; 1—W, the appendages ; x , x , hinges between the successive abdominal somites. abdomen has a slight curve, dependent upon the form and the degree of elasticity possessed by its different parts; and, in a living crayfish at rest, it will be observed that the curvature of the abdomen is still more marked. Hence it is ready either for extension or for flexion. A sudden contraction of the flexor muscles instantly increases the ventral curvature of the abdomen, and. 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 Huxley, Thomas Henry, 1825-1895. London : Kegan Paul, Trench, Tru?bner & Co.
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Keywords: ., bookauthorhuxleyth, bookcentury1900, bookdecade1900, bookyear1906
