The Sun.
London, England, 1828-12-25 00:00:00

auditus, the same as in man, and nearly of the
same form ; the labyrinth is a part of the ear
which, as far as has been examined in the four-
footed mammalia, exactly corresponds with that
of the human subject, but the cochlea exclusively
belonging to this class has often a turn more than
in roan, with some differences of less importance.
To the mammalia exclusively belongs the external
cartilaginous ear, which is wanted in the
whole class of birds; but this seeming de-
fect is amply compensated, especially in those
of the rapacious kind, by the peculiar arrange-
ment of the feathers round the opening of the
meatus ; and, in addition to this, several of the
last class, particularly the • tribe of owls, possess
a kind of valve, situate at the orifice, and con-
sisting in part of a membranous, and in part of a
muscular, texture. In its form the membrana
tympani of birds on its outer surface is convex,
and the tynfli*of the two ears are so connected
together by the air cells of- the cranium, that
they have but one ossicula auditus, by which the
membrana tympani is connected with the fenestra
ovalis, and thus supplies the place of the malleus
and stapes of the mammalia, when the part cor-
respondii;g to the mailer's is usually of a card-
la4mous structure, without any tensor tympani.
The enstachian tubes also have one common
opening on the arch of the palate, while the
labyrinth is conspicuous by large canals project-
ing from the cranium. There is likewise here a
_want of the cochlea, and, instead of it, birds
possess a short obtuse, and hollow process of
bone, directed obliquely backward 3, from the
vestibulum ; and, like the cochlea of the mam-
malia, parted off into two scalae, of which one
terminates at the fenestra rotunda, where it re-
ceives a portion of the auditory nerve, in the
same manner as the cochlea does in other a:
mals.

Besides the remarks, already made on the eus-
tachian tube of the cetacea, certain peculiarities
in other parts of the organ distinguish this
class, and, from their deviating so widely from
warm-blooded animals, they deserve particular
attention ; their want of an external ear is well
known ; the opening of the meatus is uncom-
monly small ; in the dolphin and porpoise the
bony part is but weakly attachedto the skull, and
in the common whales it is entirely separate.
The tympanuM and bulla ossea consist of a hard
bony substance, formerly, but erroneously, called
lapis manati, or tibernis ; in the same class the
ossicula auditus and the labyrinth, especially the
bony canals, are remarkably small, one reason
why they were long overlooked. The structure
,ably of the organ of hearing in the amphibia, displays
loise.. much greater variety than in the two former
daises, but there is still greater variety in the last
stale- class. Turtles, frogs, and most of the species of
be in- the lizard kind, possess, besides the semi-circular
„weds, canals, a tympanum and eustachian tube like the
greater warm-blooded animals. Ili the turtle the mem-
t what" brana tympani resembles a cartilaginous mass,
are Inet•covered externally by the common skin or tegu-
vle,thatments ; their single ossiculum is also very like
its paTttthat of birds. In frogs a large membrana tym-
On titan: is conspicuous ; their eustachian tube, which
onsidere4 short, consists of a wide opening at the fauces.
;fence th ey have also two cartilaginous ossicula, and a
t,aaachria iment of vestibulum appears, composed of
v.
nlcrit? .e soft stony substances which assume a
~tingoare conspicuous form in lizards and serpents,
r-cebuce oicin the three following orders; a sort of
astoeljoi
.meatus appears wily in the solitary in,
*r(46nat of tin.' crocodile amongst all the amphibia.
tehlis -animal
,in common with the lizard, ex-
hil also
1. the ossicula, and the stony concre-
tions4 the vestibulam already noticed. Besides
the went of a tympanum, the foramen ovale in
the salamander is closed. only by a portion of
cartilage, and its vestibulum Consists of a-soft
gone. .Fn serpents there is neither tympanum
Por eustachian tube, with very few exceptions, as
the blind worm (anguzs.fragilis), but they have
a kind of rudiment of an ossiculum. In some
-Yeller/ of cartilaginous fishes, viz. the skate,
:shark, ;and lamprey, a tubular appendix of the
vestibulum a ppears, continued backwards and
outwards, retiJesenting, as it were, the rudiment
of a tympanum ; but this form of ktructure is
confined to them :only. PrOfessor Weber has
lately afforded some information respecting the
organ of hearine-':in the bony fishes, and from his
investigation of the organ it Appears that they
possess larg• ossici,,la, that may be compared to
the malleus, incus, and stapes ; and these are
situated at tliia antavior cervical vertebrx. In
fishes provided -with a swimming bladder the
hones are so connecitd with that part of the
asrgan as to render it I.ighly probable that this
bladder is an assistant to the sense of hearing ;
three large canals, seen pro,iecting into the cavity
a the cranium, form tileir Laternal ear: there are
found also two or three neatly-formed stones in
the vestibulum, exactly oppos.ite to the termi-
nation of the auditory new e ; in several of
-the bony fishes they are . white, resembling
porcelain, and in their tes:ture are very dry
and brittle. A remarkable peculiarity distin-
guishes the internal ear of fishes, different from
that of the other three classes of t;tii-.blooded
animals, for it grows in proportion a s the fish
increases in size, and thus, by its beint,, in the
dire& ratio of the bulk of the fish, displi.ws the-
mark of its age. Though there can be no Llouht
that several insects possess the sense of liem.l-ag,
yet the organ of this sense is very uncertain ; a
part, indeed, can be distinguished in some of thLv
larger kind of the genus cancer, and this part i`
appears to be analogous to the vestibulum of the
former classes, for a small bony tube is disco-
vered on the palpw ; at each side of the root a
firm membrane closes its external opening, hav-
ing a membranous lining, on which is expanded
a nerve, having its origin
.at a common branch of
tire antennae or feelers ; and from this circum-
stance it might be conjectured that the antennae
themselves are organs of hearing, if that suppo-
sition be not refuted by the fact of some insects
having no true antenna;, and still possessing the
sense of hearing in an exquisite degree, a strong
proof of which is instanced in spiders ; and ex-
periments on other insects also prove that the
sense of hearing is not weakened by removing
the ante-mix. With regard to this sense in
worms, it is in the sepiie only that any thing
hitherto has been discovered resembling an organ
of hearing.

BEN JONSON'S RULES.--For a man to
write well, there are required three necessaries—to read.
the best books, observe the best speakers, and much exer-
cise his own style. In style, to consider what ought to be
written, and After what manner, he must first think and
cogitate in his mind his subject, then choose his words, and
examine the weight of either ; then take care, in placing
both matter and words, that his annposition be comer •;
and to do this with diligence and often. matter how
slow the style be at first, so it be laboured and accurate ;
seek the best, and be not glad to. forward conceits, or first
words, that offer themselves to us, but judge of what we ,
invent, and order what we approve. Repeat often what
we have formerly written, which, besides that it helps the
consequence, and makes the juncture better, quickens the
heat of imagination, that often cools in the time of settinc,a
down ; but the safest way is to return to our judgment,
and handle over again those things, the easiest of whicis
might make them justly suspected Discoveries edit. 1640.