Text-book of the embryology of man and mammals / by Oscar Hertwig ; translated from the third German edition by Edward L. Mark.

Date:: 1892

Credit: Text-book of the embryology of man and mammals / by Oscar Hertwig ; translated from the third German edition by Edward L. Mark. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

529/704 (page 501)

$gelatinous tissue, a large spacefilled loith perilymph, which is indicated in the diagram, fig. 282, in black. Here and there, however, connective-tissue cords remain running from one hiyer of connective tissue to the other, and serving as bridges for the nerves and blood- vessels which are distributed to the semicircular canals. Finally, a last alteration takes place in the cartilaginous envelope Fig. 282.—Diagrammatic representation of the whole organ of hearing in Man, from Wiedeksheim. Onler ear: M, M, aiiricle; Alae, meatus auditorius extemns; 0, its wall; Mt, membrana tytuijani. Middle ear: CI, CI, cavuni tynipani ; 0', its wall ; SAp, sovind-conductin!? apparatus, which is drawn as a simple rod-liko body in plaue of the auditory ossicles; tlio place t corresponds to the stapedial plate, which closes tlio fenestra ovalis ; Tb, tuba Eustachii; Tb\ its openinc; iiito the iiharynx; 0, its wall. Inner ear: the bony labyrinth (A'Z, KL') for the most part cut away ; S, sacoulus ; a, b, the two vortical membranous and osseous semicircular canals; S.c, D.e, saccus and ductus endolymiihaticus, of which the latter is divideil at 2 into two arms; Cp, cavum perilyniphaticum ; Cr, canalis reunions ; Con, mombranous cochlea, which produces at + the vestibular coscum ; Con', bony cochlea ; Sv and St, scala vestibuli and scala tympani, which at * communiciite with each other at the cupula tei-minalis (CI) ; D.p, ductus perilymphaticiis, which arises from tho sciila tympani at d and opens out at D.p'. The horizontal semicircular canal is not si)ecially designated, but is easily recognisable. by its becoming converted into bone-substancs by endochondral ossification. Thus the membranous semicircular canals are enclosed in the bony semicircular canals (fig. 282 a und h KL), which are enlarged reproductions of tlie former. Corresponding changes (fig. 282) are also accomplished in the periphery of the utriculus and sacculus [S), and lead to the formation of (1) a perilymphatic space (Cp), which is in communication with$