Transactions . ,the long axis of which forms with the long axis of thetympanic cavity a slightly acute angle. The junction ofthese two cavities converts the promontory into a boldprojecting angle of bone. The roof common to both these cavities presents no fea-tures of special interest. The height of the tympanic cavitv, directly abreast ofthe membrana tympani, is 27 millimeters (i^^g inch) andits average breadth, 25 millimeters (about i inch). Itslength could not be accurately ascertained, but it musthave been at least 50 millimeters (2 inches). ANATOMY OF THE ELEPHANTS EAR. 247 The outer wall
Transactions . ,the long axis of which forms with the long axis of thetympanic cavity a slightly acute angle. The junction ofthese two cavities converts the promontory into a boldprojecting angle of bone. The roof common to both these cavities presents no fea-tures of special interest. The height of the tympanic cavitv, directly abreast ofthe membrana tympani, is 27 millimeters (i^^g inch) andits average breadth, 25 millimeters (about i inch). Itslength could not be accurately ascertained, but it musthave been at least 50 millimeters (2 inches). ANATOMY OF THE ELEPHANTS EAR. 247 The outer wall is made up of the grooved structureswhich I have described above, and of the menihrana iyni-pani. This latter membrane, which is shown fairly wellin Figs. 2 and 4, is decidedly conical in shape, as seen from. Fig. 3. View ol tlii t\ iiniaiiic lavity troiii abovi; ami in Ilont, sliowinjc (distinctly inthe photograph hut very faintly in the engraving) the s^tall-like openings umlerthefloor of the tympanum, a part of the jagge<l wall surrounding the mouth of thewell-like excavation, the two osteopliyte.* and the grooved floor of the passage-way leading from the tymiianum to the Eustachian tube. (Slightly reduced insize.)* the side of the tympanum, while the surface of the mem-brane on the side toward the external auditory canal pre-sents scarcely any hollow ing-out at all,— barely enough tojustify the use of the expression, a shallow cone. Thislack of agreement between the two surfaces is due appar-ently to two facts : the marked curving inward of the tipend of the manubrium mallei, and the great thickness ofthe soft parts in the vicinity of the umbo of the the great resistance which the latter offers to pres-sure made at any point of its surface I should infer thatits thic
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Keywords: ., boo, bookcentury1800, bookdecade1860, booksubjectear, bookyear1868
