File:The pedigree of man - and other essays (1903) (14578086240).jpg

Identifier: pedigreeofmanoth00haec (find matches)
Title: The pedigree of man : and other essays
Year: 1903 (1900s)
Authors: Haeckel, Ernst Heinrich Philipp August, 1834-1919
Subjects: Man Evolution Man Evolution
Publisher: London : A and H.B. Bonner
Contributing Library: ASC - York University Libraries
Digitizing Sponsor: York University - University of Toronto Libraries

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, the vestibule, and a lower, the utricle. Ineach part lies an otolith, or a collection of conjoinedcalcareous crystals, near which the auditory nervespreads out on the inner wall of the vesicle, its finestfibrillae coming into connexion with the auditory ciliaplaced thereon. From the upper—vestibule—pass offgenerally three annular or semicircular canals ; their icavities are in connexion with that of the vestibule, jand, like it, are filled with fluid endolymph (Fig. 71). j From the lower—utricle—in the higher Vertebrata, is !deyeloped a peculiar organ that has been named the rJ SENSE ORGANS. 327 cochlea, on account of its outward resemblance to theshell of a snail. It would seem that this cochlea hasto do with musical perception alone, whilst the vestibuleand its derivatives are concerned in the perception ofnoises. The delicate construction of this internal auditoryorgan is so extraordinarily complex in man and in thehigher Vertebrata, that the name of labyrinth has rightly
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Fig. 71. Auditory vesicles (the so-called membranous labyrinth) ofdifferent Vertebrata. a, Man ; b, Calf ; c, Pike ; d, Hawk ;e, Frog. 1, 2, 3, the three semicircular canals (1, horizontal;2, superior; 3, posterior). 4 Part common to the superiorand posterior canals. 5. Ampullae (enlargements). 6. Ves-tibule. 7. Utricle. SENSE ORGANS. enough been given to it. Yet the astounding complexityof structure presented by this labyrinth, to the outletfrom whose mazes the Ariadne-threads of embryologyalone can be our guide, is primarily nothing more thana simple auditory vesicle, and, like the simple auditoryvesicles of the lower animals, has been developed fromthe integument. This notable discovery was made in1831 by Emil Huschke, in Jena. In order to convinceourselves as to its accuracy we have only to examine afowls egg that has lain for a day and a half in thehatching machine. In it we see on the side of therudimentary head of the embryo chick a pair of shallowdepressions lined by cells of

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