. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology; Zoology. 206 BULLETIN : MUSEUM OF COMPAKATIVE ZOOLOGY. set.' the three {mal), which projects from the lateral and posterior wall of the cyst, is without seusorj organs of any kind. Its wall is irregularly cui'ved and pitted (Plate 9, Fig. 47 mat.,), while portions of it are even calcified. At one point its walls are constricted to form a neck, which b3ars a large hammer-like head (Fig. 47). This is the "Hammer" of Hensen, compared by him to the malleus of the vertebrate middle ear. Figures 43, 4S, and A show
. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology; Zoology. 206 BULLETIN : MUSEUM OF COMPAKATIVE ZOOLOGY. set.' the three {mal), which projects from the lateral and posterior wall of the cyst, is without seusorj organs of any kind. Its wall is irregularly cui'ved and pitted (Plate 9, Fig. 47 mat.,), while portions of it are even calcified. At one point its walls are constricted to form a neck, which b3ars a large hammer-like head (Fig. 47). This is the "Hammer" of Hensen, compared by him to the malleus of the vertebrate middle ear. Figures 43, 4S, and A show the relative position of this hammer to the. * Figure A. Model of the lumen of the left otocyst of Carcinus, dorsal view, tne upper wall of the sac removed. The cavity of the sac was modelled in wax from serial sections under a masjiiification of 50 diameters, and a plaster cast of the model photf'^raphed natural size. In making; the cut this was reduced to a mafrnitication of 'S'-i diameters, a., anterior; m., median; set,', group hairs; set. fil., thread hairs; set. ta., hook tiairs. rest of the sac. It serves merely for the attachment of the short, thick, powerful muscles of the antennule which keep the latter in almost con- stant motion, and has probably nothing whatever to do with the sensory functions of the otocyst. b. Sensory Cushions. Of the three projections noted, the remaining two are sensory and bear sensory hairs (Plate 10, Fig. 55, set. to., set. fil.). The smaller of these (set. ta.), located on the median portion. 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 Harvard University. Museum of Comparative Zoology. Cambridge, Mass. : The Museum
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Keywords: ., bookauthorha, bookcentury1800, bookdecade1860, booksubjectzoology
