. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. EXTENSOR MECHANISM IN SPIDERS 47 proximally fur a short distance. These plates are flattened clorso-ventrally and are limved proximad. The plate in the femoropatellar joint was descrihecl hy Gauhert (1892) hut its presence has been consistently ignored by subsequent investigators, and the homologous structure in the tibio-metatarsal joint has apparently never been reported. From the proximal margin of these plates arise the tendonous strands whereby the metatarsi loiu/i and patellae loiujl are respec- tively
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. EXTENSOR MECHANISM IN SPIDERS 47 proximally fur a short distance. These plates are flattened clorso-ventrally and are limved proximad. The plate in the femoropatellar joint was descrihecl hy Gauhert (1892) hut its presence has been consistently ignored by subsequent investigators, and the homologous structure in the tibio-metatarsal joint has apparently never been reported. From the proximal margin of these plates arise the tendonous strands whereby the metatarsi loiu/i and patellae loiujl are respec- tively inserted. Moreover, a few isolated muscle fibers, arising from the distal dorsal wall of the femur and inserting on the dorsal surface of the chitinous plate (Fig. 2 Icp). seem to be uniformly present in sagittally cut It was first thought that these fibers might be artifacts resulting from the cutting pro- cedure, but care was taken to make the cut from different directions with respect to FEMUR. PATELLA FIGURE 2. Photomicrograph of the femoro-patellar joint of Miranda anrantia. (Mid- sagittal section.) CP = chitinous plate, FPB — flexor patellae bilobatus, FPL = flexor patellae longus, LCP = levator of chitinous plate. the femoro-patellar joint, and in all cases these fibers were found to lie in almost identically the same position on the dorso-ventral median line of the femur. It ap- pears, therefore, that these few fibers form an heretofore undescribed muscle, the function of which is obviously elevation of the chitinous plate. It is probable that this group of fibers has been overlooked because they run in nearly the same direc- tion as the more laterally located distal fibers of the patellae bilobatus. Care- tul examination of Figure 2 will show, however, that these fibers of the large flexor muscle insert on the chitinous lip of the patella, not on the plate. The existence of 3 The above sagittal preparations were made by first fixing the isolate
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
