189 
ala vestibuli and 
-like protrusion from the vestibule, as 
st mammalian whorl, and very incompletely divided into se 
seala tympani by a 
of course, both these ‘‘ windows” are closed by membranous 
chlear cavity and its bony or cartilaginous contents are only the 
THE ANATOMY OF BIRDS.—NEUROLOGY. 
Now in birds the co 
os of such structure— a strap-shaped or tongue 
beginning 
stapes were unstepped (in life, 
if a part of the fir 
curtains).’ 
Fia. 84. Fia. 8b. Ere. 86. ~ Fia. 87. Fic. 88. 
Figs. 84, 85, membranous labyrinth of Haliactus albicilla, x2. a, b, cochlea; b, its saccular extremity (or lagena); c, vestibule ; 
q, its utricle; d, anterior or superior vertical semicircular canal; ¢, external or horizontal semicircular canal; 7, posterior or inferior 
vertical semicircular canal; hk, membranous canal leading into aqueduct of the vestibule; /, vascular membrane covering the scala 
vestibuli; opposite this, at 7, are seen the edges of the cartilaginous prisms in the fenestra rotunda; from the edges of these cartilages 
proceeds the delicate membrane closing the opening of the cochlea (not shown in the fig. ). 
Fig. 86, part of the superior vertical semicircular canal, showing its ampulla (which is the dilatation of the base of any semicircu- 
lar canal), nerve of ampulla, artery and connective tissue of the perilymph, x 3. @, that part of the vestibule (alveus) next to the ampulla; 
b, the dilatation of the ampulla at its vestibular opening; c, where it passes into the canal proper; d, the canal, furnished with connec- 
tive tissue of the perilymph along its concave border and sides, as appears clearly at the sections e and; g, nerve of the ampulla; h, 
artery of the connective tissue, running beneath it, remote from the wall of the duct. 
Fig. 87, cochlea, x 3. a, external, 6, internal, cartilaginous prism; ¢, membranous zone; d, saccular extremity of the cochlea, or 
lagena; e, vascular membrane; /, auditory nerve, its middle fascicle penetrating the internal cartilaginous prism, to reach the mem- 
branous zone by its terminal filaments; 9, auditory nerve, its posterior fascicle, running to the most posterior part of the lagena; h, 
filament to ampulla of posterior or inferior vertical semicircular canal. 
Fig. 88, section of the cochlea, X 3. @, vestibular surface of external cartilaginous prism, extending into d, the lagena; c, section of 
the membranous zone; ec, Huschke’s process of the fenestra, which, with the margins of the cartilaginous prisms, affords attachment 
to the blind sac f, occluding the fenestra of the cochlea; y, spongy vascular membrane of the scala vestibuli; h, auditory lameile of 
Treviranus; é, canals in posterior wall of the lagena, by which the nervous filaments enter its cavity. 
(From Ibsen’s Anatomiske Undersgelser over Prets Labyrinth. 4to, Kjpbenhayn, 1881, p. 17, pl. 1, figs. 13-17.) 
Hee ST sf Oo b ~ a) Set ees D) Se es ! 7) D1 1 oH ee a | S 
BASAL SASME SS SSS SP A* SSR ees sss. Bsesasgeaast 
SSSSPE RSs Pe gh kaens SS eta sSREEL EES EE Se 
Seah ke ge SH eee ek Hei SREseeoeeae ss SS aise 
=) aH epere Ff aoo wo ay fost os oc} o Ba So Se . Sp oer, 
H Ss pet. 7 a 4 od ? — a sn iso: a Cro A o o “3 77) 
SeSSSE RH E748 Be. Ro bette bk esess eo tot 8 Se 
Srey aero ie =a leliale cs eo feet see ey et Siro Saw “a 6 ‘ e a + a) So 
a= iss] Oo Mm | ° 5 © “4 2 e e oa =| Oo P| 
2 BSE RES eRe oC eAS ESS Sema sebeeteg-8F sia 
Ona 229 3 @ 8 ig ere ais ae sen Sl ee ee ts) wy & ra, Se a ee 
= a = ae o co a a 2 Sy iS) | 5 > ay eS cate} ‘e q a, A = q b = 3S 2 A 5 a 2 =| KS ox} 
“4 eo C a) > = a i A ] 
BPEaaSSAaS ~ oes B08 9 Be SP delete eB ace See ee eee 
a ee TO: eS “SS! res q o 2 Ss = = Sic oom a 2 8 2, =| = SS 
mM DD A -x re Seg | =| = > ; Se fore 2 See Ss H's ao 
Oia Site) Oy Seo I ee ee ie ee Oo S-a & eee) os S) A ara se ae dics OSs, 
B23 SS 2 Oo os we 2 eee Sete aa Soe See Seve. S54 Co Seo SO 
Ma oF SP SS SF OH 8S Pe Se eS Re pepe ety) oe enn De Oat eS ame a nw Om Ve a G 
and 
In the 
approximately mutually perpendicular, in the three 
, 
anum by fenestra ova- 
opening into tymp 
’ 
the three semicircular canals are the (a) anterior or 
rior vertical, and the (c) external or horizontal 
internus by the course of the auditory nerve. 
ere smoothed out, it would about hold a pea. 
g semicircular canal 
auditorius 
eparate or unitin 
superior vertical, the (b) posterior or infe 
Ss 
} 
mouths of the 
In the language of human anatomy, 
eagle, if its irregularities of contour w 
the planes of their respective loops are 
lis; conducting to meatus 
