. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. BLUE CRAB CHELAE 323 stainless steel cylinder, the other bar was attached to a piston which inserted into the cylinder. The cylinder was filled with vacuum pump oil. Squeezing the bars together raised the pressure inside the cylinder which was shown on a pressure gauge. The transducer was calibrated by hanging a weight on the proximal and distal ends of the steel bars and recording the deflection on the pressure gauge. Force recordings were taken from both crusher and cutter chelae of the crabs. The points of force applicati
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. BLUE CRAB CHELAE 323 stainless steel cylinder, the other bar was attached to a piston which inserted into the cylinder. The cylinder was filled with vacuum pump oil. Squeezing the bars together raised the pressure inside the cylinder which was shown on a pressure gauge. The transducer was calibrated by hanging a weight on the proximal and distal ends of the steel bars and recording the deflection on the pressure gauge. Force recordings were taken from both crusher and cutter chelae of the crabs. The points of force application along the bars of the transducer and along the dactyls were measured with dial calipers. The force applied to the transducer by the dactyl (Fbar) was used to calculate the force applied by the closer muscle to the dactyl at the point of apodeme insertion (F,). Assuming the dactyl pivot is frictionless, then F, = (Fbar)(Lhar)/L, where L] is the distance from the dactyl pivot to the point of apodeme insertion onto the dactyl and Lbar is the distance from the dactyl pivot to the point offeree application along the dactyl (Fig. 2). The product of (Fi) (L,) divided by the distance from the dactyl pivot to any point x along the dactyl equals the dactyl force at point x. Other measurements included carapace width, chela length, chela height, chela thickness, mechanical advantage (L) divided by the distance from the dactyl pivot to the dactyl tip), angle of muscle fiber pinnation, and surface area of both sides of the apodeme. After removing the dorsal surface of the propodus and the chela opener muscle, the dactyl was fixed open at 30° (to simulate its crushing position) and viewed under a dissecting microscope equipped with a camera lucida drawing tube. The apodeme and several muscle fibers on both sides of the apodeme were traced; the angles of muscle fiber attachment onto the apodeme (angles of pinnation) were then measured with a protractor. The apodeme was subsequently CRUSHE
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
