. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. STATOLITH HAIR \lte ANTERO-DORSAL GROUP HAIR DORSAL THREAD HAIR. Fig. 69. Sensory hairs of statocyst. Thread hairs (figs 68, 69), which are long and slender with a tapering plumed tip, are distributed over the dorsal wall. Similar hairs in other decapods are stimulated, not by positional changes, but by movements of the fluid contents of the statocyst; they have been defined by Dijkgraaf (1956) and Cohen & Dijkgraaf (1961) as rotation receptors which are sensitive to movements about vertical and
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. STATOLITH HAIR \lte ANTERO-DORSAL GROUP HAIR DORSAL THREAD HAIR. Fig. 69. Sensory hairs of statocyst. Thread hairs (figs 68, 69), which are long and slender with a tapering plumed tip, are distributed over the dorsal wall. Similar hairs in other decapods are stimulated, not by positional changes, but by movements of the fluid contents of the statocyst; they have been defined by Dijkgraaf (1956) and Cohen & Dijkgraaf (1961) as rotation receptors which are sensitive to movements about vertical and horizontal axes. The longest hairs (figs 68, 69) within the statocyst occur usually in pairs along the lateral and medial margins of both walls, and each is distinguished by a fine, tapering, slightly curved, plumose tip. They are probably comparable with the free-hook hairs mentioned by Dijkgraaf (1956) and Cohen & Dijkgraaf (1961), who have suggested that they may assist in governing the rotatory reflexes initiated by the responses of the thread hairs to stimulation. The group hairs described by Prentiss (1901) in proximity to the statocyst aperture of Carcinus maenas differ from the other kinds of hairs in being short, coarse, and unplumed. This definition does not apply to any of the statocyst. 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 South African Museum. Cape Town : The Museum
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
