Text-book of comparative anatomy . bend in one plane, as is indeed the case in therow of body segments. But the two hinges of the consecutive joints are in reality soplaced as to make free movement possible. The exoskeleton of the body segments isrelated to the exoskeleton of the basal joints of the appendages which it carries justas a large joint of a limb is to a smaller. The muscles which on the one hand areinserted in the exoskeleton of the first joints of the extremities, by preference attachthemselves on the other to the tergum of the corresponding segment. The mechanism of the forceps (
Text-book of comparative anatomy . bend in one plane, as is indeed the case in therow of body segments. But the two hinges of the consecutive joints are in reality soplaced as to make free movement possible. The exoskeleton of the body segments isrelated to the exoskeleton of the basal joints of the appendages which it carries justas a large joint of a limb is to a smaller. The muscles which on the one hand areinserted in the exoskeleton of the first joints of the extremities, by preference attachthemselves on the other to the tergum of the corresponding segment. The mechanism of the forceps (chehe) of the Cray-fish (Fig. 233) is as forceps is formed by the two terminal joints of the chelate foot. The lastjoint but one is produced into a pointed process (zf). The last joint (eg) articu-lates with it in the ordinary way by means of two opposite hinges. Round the hinges the two joints are connected by means of a thin and flexibleinterarticular membrane. Two muscles serve in the way shown in the illustration A.
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectanatomycomparative
