. On the anatomy of vertebrates [electronic resource] . prominent, the anti-tragus is better marked : a low fold represents the 6 lower crus of the anthelix, the upper one and the rest of that fold arewanting. It is only in the orangs and chimpanzees that theparts defined in the human auricle are represented. The freemargin is reflected to form a e helix, but not to the same degreeas in Man : the anthelix, beginning above with both ( upperand i lower crus, is continued to the antitragus ; both scaphoidnavicular fossae are defined, as well as the cavity of the conchaand the tragus: the lobulus
. On the anatomy of vertebrates [electronic resource] . prominent, the anti-tragus is better marked : a low fold represents the 6 lower crus of the anthelix, the upper one and the rest of that fold arewanting. It is only in the orangs and chimpanzees that theparts defined in the human auricle are represented. The freemargin is reflected to form a e helix, but not to the same degreeas in Man : the anthelix, beginning above with both ( upperand i lower crus, is continued to the antitragus ; both scaphoidnavicular fossae are defined, as well as the cavity of the conchaand the tragus: the lobulus is not pendant as in Man. In thechimpanzee ( Troglodytes niger) the external ear is larger abso-lutely than in the great gorilla ( Troglodytes Gorilla). In all the figures of the otosteals previously given the stapes isdrawn at right angles to its natural position, in which only a fore-shortened view of the bone could be had, as in fig. 178, where itis shown with its base a applied to the e fenestra of the vestibule. ORGAN OF HEARING IN MAMMALIA. 2:37. Osseous labyrinth and otosteals, Human ; mas Of the three semicircular canals the shortest, c, has a nearly hori-zontal position : the other two are more vertical: the upper onerises at the convexity of its curve, d, above the level of the uppersurface of the petrosal: it is that which, Avith its arch-area, ismost free in many lower Mammals. The lower vertical canal, e,unites by its upper extre- 178mity with the contiguousone at /; the commonopening of which is shownat m, fig. 163. Each ofthe semicircular canals ex-pands at one extremity ;but this is more markedin the membranous canals,fig. 165, where the dilata-tions, a, b, c, are termedampullae : the bony ca-nals are wider in propor-tion to the membranousones in Man than in most Mammals, and consequently the peri-lymph is more abundant. This is seen in fig. 179, which repre-sents the osseous labyrinthlaid open, with the mem-branous labyrinth in situof the human ear. Of thelatte
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