. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 322 C. K. GOVIND AND J. A. BLUNDON Campbell, 1981). The crusher closer muscle is composed of all slow fibers while the cutter closer muscle has a majority of fast fibers and few slow fibers (Jahromi and Atwood, 1971; Lang el <://., 1977; Ogonowski el at., 1980). The blue crab, Callinectes sapidus Rathbun, also has dimorphic crusher and cutter chelae which have different functions in feeding. The crusher, which is capable of generating much more force than the cutter, is used in crushing mollusc prey, while the cutter mani
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 322 C. K. GOVIND AND J. A. BLUNDON Campbell, 1981). The crusher closer muscle is composed of all slow fibers while the cutter closer muscle has a majority of fast fibers and few slow fibers (Jahromi and Atwood, 1971; Lang el <://., 1977; Ogonowski el at., 1980). The blue crab, Callinectes sapidus Rathbun, also has dimorphic crusher and cutter chelae which have different functions in feeding. The crusher, which is capable of generating much more force than the cutter, is used in crushing mollusc prey, while the cutter manipulates the prey item and tears at the exposed flesh (Blundon and Kennedy, 1982). However, there is little available data on the functional and structural differentiation of the dimorphic chelae or on the composition of their closer muscles. The present study addressed these points. Another reason for studying blue crabs is the apparent reversal of chela laterality that they display. The normal chela laterality is right crusher and left cutter (Przibram, 1931). However, the reverse configuration of left crusher and right cutter which occurs in a small percentage () of the population and among large crabs only, suggested to Hamilton el al. (1976) that this configuration could arise when the crusher is lost and in its place a cutter regenerates. The existing intact cutter transforms into a crusher. Reversal of chela laterality found in the snapping shrimp Alpheus, involves a transformation in the fiber composition of the closer muscles (Stephens and Mellon, 1979; Mellon and Stephens, 1980). It was therefore of interest to determine the fiber composition of the closer muscle in blue crabs with the normal and reversed chela laterality. MATERIALS AND METHODS Chela performance in vivo Blue crabs weighing between 150 g and 260 g were caught with crab pots in the Choptank River, Chesapeake Bay, in June 1984. They were placed in water tables (at Horn Point Environmental Laboratory,
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
