OST 
and flat; and the crown is white, marked with 
oblong dufl<cy fpots. The cheeks, chin, belly, 
and breaft, are white, the laft being fpottcd with 
a dull yeltow; and from the corner of each eye 
there is a brown bar, which extends along the 
fides of the neck towards the wings. The legs 
are fhort, thick, ftrong, and of a pale blue co- 
lour: the outer toe eafily turns backv/ardsj and 
it's claw is larger than that of the inner toe, in 
which peculiarity it differs from all other preda- 
ceous birds. 
OSTRACION. A large genus of fifhes of 
the clafs of amphibia nantes in the Linnseandif- 
tribution of nature: the characters of which are; 
that there are no belly-fins ; and that the fkin is 
always hard, and often prickly. Linnseus enu- 
merates nine fpecies. 
According to Artedi, the characfters of the Of- 
tracion are thefe : there is no branchioftege mem- 
brane; the figure of the body is globofe orfphe- 
rical, oval,- oblong, fquare, or conic ; the n<in is 
ufually hard, and befet with rigid and hard fpines, 
though in fom fpecies it is wholly fmooth ; there 
are no ventral fins; the others are five in number; 
the mouth is fmall ; the teeth are large ; the eyes 
are covered with the common ik'm of the head ; 
and the lips are retraClile, though in their natural 
ftaie they cover the greater part of the teeth. 
OSTRACODERMATA. An Ariftotelian 
appellation for that clafs of fhells called teftaceous, 
in oppofition to the cruftaceous animals, or ma- 
lacoftraca. Ariftotle thus defines thefe creatures : 
they are foft within, but hard without; their fhells 
may be bruifed, or broken ; but their parts cannot 
be torn afunder, as in the cruftaceous kinds. 
OSTREA. See Ovster. 
OSTRICH. A genus of birds in the Lin- 
n£can fyftem, of the order of grallse; the charac- 
ters of which are: the beak is of a conical fhape; 
the noftrils are ovated; the wings are unfit for 
flight; and the feet are formed for running. 
This naturalift enumerates three fpecies; the 
common, or camel Oftrich; the caffowary; and 
the nhanduguacu. 
Ostrich, Common, This curious bird ap- 
pears in fome meafure to unite the clafs of qua- 
drupeds and birds. Wkile it has the general out- 
line and properties of a bird, it neverthelefs retains 
many traits of a quadruped. In it's general ap- 
pearance, it refembles the camel, and is almoft as 
tall; it is covered with a plumage more nearly re- 
fembling hair than feathers; and it's internal 
parts bear as great a fimilitude to thofe of the qua- 
druped as of the bird creation. It may therefore 
be confidered as an animal intended to fill up the 
chafin in nature which feparates one clafs of be- 
ings from another. 
The Oftrich is certainly the largeft of all birds, 
being in it's native climates nearly as tall as a man 
on horfeback ; and even fome of thofe which have 
been imported into England, have meafured up- 
wards of feven feet in height. The head and bill 
fomewhat refemble thofe of a duck; the neck may 
be likened to that of a fwan, except that it is much 
longer; and the legs and thighs are formied like 
thofe of a hen. It is vifually upwards of feven 
feet high from the top of it's head to the ground; 
but, from the back, it is only four; confequently 
the head and neck are above three feet long. From 
the top of the head to the rump, when the neck is 
extended in a right line, it is fix feet long; and 
the tail is about one foot more; while one of the 
naked wings is about a foot and a half; bur^ when 
OST 
the feathers are ftretched out, it is about tliree 
feet. 
The plumage of this bird is generally a mix- 
ture of black and white, though fome var'etits 
are obferved to be grey. The largeft feathers, 
which are fituated at the extremity of the tail and 
wings, are commonly white; the next row is black 
and white; and, of the linall feathers on the bade 
and belly, fome are blaclc, and others v/hitc. 
There are no feathers cither on the fides, the 
thighs, or under the-^ings; the lower part of the 
neck, about half w^ up, is covered with ftill 
fmaller feathers than 6h the belly and back; and 
thofe, like the former, are alfo of different colours- 
All thefe feathers are of the fam.e nature, and pe- 
culiar to the Oftrich; for other "birds are clothed 
with different forts of plumage, partly foft, and 
partly hard. 
The feathers of the Oftrich being almoft all as 
foft as down, are abfolutely unfit to help t!ie ani- 
mal in flight, and ftill lefs adapted for defence 
againft external injury. The feathers of other 
birds have their webs broader on one fide than on 
the other, but thofe of the Oftrich have their 
ftiafts exa6lly in the centre. The upper part of 
the head and tlie neck are covered with a very fine 
clear white hair, ftiiny like the briftles of a hog; 
and in fome places there are tufts of this kind, 
confifting of about tv/elve hairs, whi-ch all ilTus 
from a fingle fhaft about the thicknefs of a pin. 
At the extremity of each wing there is a kind of 
fpur, refembling the quill of a porcupine, about 
an inch long; and, about a foot iov/er, there is 
another of the fame kind. The neck, being def- 
titute of feathers, appears very flender in propor- 
tion to the magnitude of the bird ; and the fkin in 
this part is of a livid flefh-colour, which fome 
improperly denominate blue. The bill is fhort 
and pointed; the external form of the eye is like 
that of a man, the upper eye-lid being adorned 
with eye-laflies, which are longer than thofe on 
the lid below; the tongue is very fmall, fhort, 
and compofed of cartilages, ligaments, and meni- 
branes, intermixed with fiefliy fibres : in fome, it 
is about an inch long, and very thick at the bot- 
tom; in others, it is but half an inch, and a little 
forked at the extremity. The thighs, which are 
very large and flefliy, are covered Vv^ith a white 
fl<:in, having a reddifh tinge, and wrinkled in the 
form of a net. Some individual birds have very 
fmall feathers difperfed over the thighs ; and others 
have neither feathers nor wrinkles. What are 
called the legs of birds, in the Oftrich arc co- 
vered before with large fcales. The end of the 
foot is cloven; and has two very large toes, which, 
like the leg, are covered with fcales: thefe toes 
are of unequal fizes; the largeft, which is on the 
infide, is feven inches long, including the claw; 
and the otiier toe, which is about four inches 
long, is deftitute of a claw. 
Having furveyed the external figure of the 
Oftrich, we next advert to the internal, which 
is formed with no lefs furprifing peculiarity. At 
the top of the breaft, under the flvin, the fat is 
two inches thick ; and on the fore-part of the belly 
it is as hard as fuet, and in fome places about two 
inches and a half thick. It has two diftinct fto- 
machs: the firft, which is lov/ermoft, in it's natu- 
ral fituation fomewhat refembles the crop in other 
■birds; but it is confiderably larger than the odier 
ftomach, and furnifl:ied with iftrong n^ufcular 
fibres, as well circular as longitudinal: and the fe- 
cond ftomach or gizzard, v/hich is externally 
fhaped 
