4 Oenf.rai. Characters. REPTILES. General Characters. 
the animal heat, musculai’ force, and all the other func- 
moveable, but in the tortoises and turtles the air is 
tions dependent upon respiration, will be diminished.” 
introduced into the lungs by a sort of act of deglutition 
Hence it follows that reptiles possess but little power of 
or swallowing. 
sustaining muscular action, for though several species 
Tlie integument or skin of reptiles is dry and hard. 
are capable of moving rapidly for a short time, it is only 
and is covered with either horny plates or with scales, 
when they are supplied with that degree of temperature 
which structure forms an excellent character for 
externally which is denied them from an internal source. 
arranging them in two large groups, the scaly and 
that they are capable of exerting any energy at all. 
shielded coat of mail reptiles. Their limbs are either 
When deprived to a certain extent of exteimal heat. 
four or two in number, or are wanting altogether, at 
the^' then, as has been mentioned above, pass into a 
least externall 3 ''. When present, they are in almost 
state of torpidity or hibernation. In temperate and 
all cases very short, and so formed as in most instances 
cool climates, the lizards and serpents retire during 
to prevent their possessors having a rapid motion. 
winter to holes in trees, under stones, beneath dead 
They possess the senses of sight, hearing, taste, smell. 
leaves, or in such like places, where many species. 
and touch. In general the eyes are small, and not so 
especially serpents, congregate in large numbers, and 
well developed as in the higher classes of animals. 
ax’e found closely entwined together. The land tortoises 
They are largest in the tortoises, crocodiles, and lizards, 
take refuge from the cold in excavations, which they 
and smallest in the serpents. In these latter animals 
often dig for themselves, and the fresh-water tortoises 
there are no apparent eyelids, and, in consequence, 
in holes in the muddy banks, or in the mud at the 
their eyes seem fixed and always wide open. In the 
bottom of their native lakes or rivers. “ Here they 
lizards we find two lids; the tortoises and crocodiles 
j)ass the winter in a state of almost lifeless repose, the 
have three, whilst the chameleons have only one, and 
functions of life so nearly suspended, that none of the 
that a very singular one. The sight itself in general 
external signs of its existence are visible. The circu- 
is very acute, for on this sense depends their pursuit 
lation is extremely slow, the respiration apparently 
of food and their perception of the approach of enemies 
altogether stopped, digestion absolutely suspended. 
The organ of hearing is, in general, not so highly de- 
Tlxe return of the genial warmth of spring calls them 
veloped in Reptiles as in Mammalia and Birds. They 
again into action. The circulation is restored, the 
never possess any external ear; and the sense of hear- 
blood is again fitted for its various offices by the return 
ing varies a good deal in the different orders. It is. 
of regular respiration, the functions of the digestive 
perhaps, the most obtuse in the tortoise tribe, and the 
organs are again performed, and the animal resumes 
most acute in serpents. In these latter animals and in 
its former habits, without having undergone any 
lizards we see that the sound of music imparts to them 
material change.”* A similar state of torpiditj' takes 
great delight, aud this is well known to the serpent- 
place in many reptiles within the tropics. This 
charmers of the East. In most cases the internal organs 
summer torpidity, or, as it may be called, estivation, is 
of hearing are entirely covered by the scalyr investment 
governed by the times of drought. Crocodiles or 
of the head; but in the crocodiles, “the external orifice. 
alligators, and large boas, are frequently found in a 
instead of being thus permanently closed, is provided 
lethargic state in the dry mud, and Humboldt’s anec- 
with a firm, hard, moveable lid, or operculum, by means 
dote has been frequentl}'' quoted, of an Indian in 
of which the aperture may be either stopped or kept 
South America having built a hut over the spot where 
open. Thus, while basking on the margin of the river, 
a crocodile lay buried in the hardened clay, and was 
or lying there in ambush for prey, the crocodile has 
only made aware of his mistake by the rains moisten- 
the power of raising the earlid, in order to listen atten- 
ing the ground, and bringing the huge creature into 
lively to every noise ; but when he dives beneath the 
animation again. 
water, either for safety or to drown the victim he has 
All Reptiles possess true lungs, and their respiration 
seized, the entrance of water into the auditory cavities 
is exclusively pulmonary throughout the whole of 
is prevented by the firm shutting of the lid, which 
their existence. This forms one of the most impor- 
accurately fits the orifice.”* The sense of smell is 
tant differences which have induced zoologists to sepa- 
comparatively feeble in reptiles. Indeed their manner 
rate the Frogs and Toads, &c., from true Reptiles; 
of living would lead one to infer that they would have 
the respiration in these animals, and those arranged 
little use for acuteness in that organ. It is much the 
along with them, being carried on by means of 
same with the sense of taste. In a large proportion of 
branclnoi or gills during the earlier period of their life. 
reptiles their food is swallowed whole and entire, and 
changing — in some totally, and in others only partially 
the structure of the tongue in some of those which tear 
— to the pulmonary character, in the adult condition. 
their prey, as the crocodiles, is such as to show that 
The lungs are two in number, right and left, nearly of 
that organ is not fitted to be of much use for the pur- 
equal size, except in the serpents, and cellular or 
pose of tasting. The sense of touch does exist in rep- 
spongy. Their structure differs somewhat in the 
tiles, but only in a low degree. The skin of their bodies 
different orders, but in all it is such as only to admit a 
and feet, covered with dry scales or horny plates, 
jiortion of the venous blood from the heart, instead of 
does not seem adapted for the possession of any acute 
the whole. In the Saurian Reptiles and Serpents, the 
degree of sensation; and even in those species, such 
act of respiration is carried on mechanically by the 
as the Geckos especially, in which the toes are dilated. 
action of the ribs, which are more or less free and 
this structure is more for the purpose of enabling 
* Bell — Bdtisli Reptiles. 
* Martin — History of Reptiles. 
