y Kui'ENTs. REPTILES. SicRrBNTs. 35 
by the term sloughing. It comes off in a single piece 
from the head to the tail, without tearing in any part ; 
and after it has been thrown oft' it preserves all the 
external characters so well, that a person may recognize, 
by finding the skin, the species of serpent to which it 
had belonged. The eyes have no true eyelids, but are 
covered by the common skin, which is perfectly pellucid. 
They have no visible external ear, and their nostrils are 
situated on the side of the front part of the muzzle. 
Serpents have a very capacious and very dilatable 
mouth. This arises from the very peculiar disposition 
of the bones of the jaws and the muscles which move 
them. The bones forming the jaws and the face are 
all loose and disunited, being connected only by skin 
and ligaments. The upper jaw is in two pieces, is sus- 
pended, as it were, distinct from the cranium, and acts 
Bubordinately to the movements of the lower jaw. The 
lower jaw is also in two pieces, and consists of two dis- 
tinct lateral branches, each branch being, in fact, itself 
made up of two portions, united by a loose kind of 
suture. Instead of being secured b^^ firm joints to the 
skull, the lower jaw is attached on each side by a lax 
joint to a movable bone, called the tympanic portion of 
the temporal bone. This joint admits of a natural kind 
of dislocation, so that it gives way in the act of swal- 
lowing, and recovers its position when the prey is 
swallowed. From this mobility of the jaws and bones 
of the face, the mouth is rendered capable of being 
very much increased in size; and the animal is enabled 
to take into it the bodies of animals of a large size. 
The tongue of these reptiles is long and very movable, 
and is capable of being withdrawn into a sort of sheath 
at its base. It is slender, tapering, and forked at the 
tip. This forked nature of the tongue gives it some- 
what of a malignant appearance, and accordingly, by 
the ignorant, it is looked upon as a deadly weapon, and 
called the dart. Shakspeare has embodied this idea in 
several passages of his immortal works. Thus King 
Lear, telling of the wrongs sustained by him from his 
daughter Goneril, is made to say — 
“ She has abated me of half my train ; 
Looked black upon me; struck me with her tongue, 
Most serpent-Ulce, upon the very heart.” 
Again, in the “ Midsummer Night’s Dream,” Hermia, 
reproaching Demetrius for the supposed murder of 
Lysander, says — 
“ And hast thou killed him sleeping ? 0 brave touch ! 
Could not a worm, an adder, do so much ? 
An adder did it; for with doubler tongue 
Than thine, thou serpent, never adder stung I" 
This double tongue, however, possesses no hurtful pro- 
perty, It forms, in ffmt, the chief organ of touch ; 
appears rather destined to seize aliments than to per- 
ceive savours; and evidently serves more for assisting 
the animal to swallow, than for tasting its food. The 
teeth of serpents are numerous, and are inserted upon 
all the bones of the mouth, as well as the two jaws. 
The number and proportion vary, and they form good 
characters for distinguishing genera and species. 
Serpents, indeed, are generally divided into two 
groups, the poisonous and harmless; the chief, and 
sometimes almost only perceptible difference between 
them, consisting in the structure of their teeth. In the 
latter group, the harmless or Colubrine serpents, the 
teeth are disposed in two rows in the upper jaw, and 
a single row in the lower. They are sharp-pointed, 
regularly inclined backwards, so that the hand may be 
passed down over them with impunity, but not drawn 
back; for then they pierce the skin immediately. 
Hence while they offer no impediment to the passage 
of food, they securely detain the struggling victim. In 
the poisonous or Viperine serpents, on the contrary, 
there is only a single tooth oh each side of the upper 
jaw, properly speaking ; these are the poison fangs, the 
other teeth being placed in a single row on the bones 
of the palate. The lower jaw is only partially furnished 
with teeth. The poison fangs are thus decribed by Mr. 
Waterton : — “ They are invariably on the upper jaw, 
but they are not fixed on the bone. They are always 
curved downwards like the blade of a scythe. There 
is a little opening on the convex part near the point. 
From this opening to the point, which is as sharp as 
a needle, the fang is quite solid, but hollow from it to 
the root. This point may aptly be styled the pioneer 
of death, as it makes the wound into which the poison 
of the irritated serpent flows through the hollow part of 
the fang. It is the fatal weapon which causes a snake 
to be so much dreaded, and condemns the whole race 
to universal detestation; although, in fact, not one 
snake in ten has been armed by nature with the deadly 
fang. When not in readiness to inflict a wound, these 
two poison fangs resume a recumbent position, so as 
not to interfere with the action of the ordinary teeth, 
which are firmly fixed and are very small, and most 
admirably formed to seize their prey, and to send it 
down into the stomach.” * The glands which secrete 
the poison are found on the sides of each branch of the 
upper jaw behind the orbit, and almost below the skin. 
Two muscles destined to raise the fangs, traverse them 
from back to front, one outwards, the other underneath, 
so that they cannot act without compressing the gland 
and impelling the poison into its excretory canal, which 
conducts it to the base of the fangs, where it penetrates 
by a cleft which prevails throughout their whole extent, 
and opens toward the point obliquely, “ like the cut 
of a pen.” 
When the irritated animal bites its victim, these fangs 
are raised iqrright by means of the mobility of the jaw- 
bones. They never strike their prey more than once ; 
should they miss their aim they withdraw themselves 
for a time. “ Armed with a poison fang,” says Mr. 
Waterton, “ the snake at one single stroke (never 
repeated, as far as I could see) avenges itself on the 
unfortunate animal which has trodden upon it, or has 
put it in bodily fear by disturbing its repose.” The 
nature of these poison fangs, and the situation of the 
gland which secretes the venom, seem to have been 
known to the Jews at a very early period. David in 
his prayer to be delivered from Saul and Doeg, in the 
140th Psalm, says — “ Deliver me, 0 Lord, from the 
* This description of the poison fangs applies chiefly to the 
pre-eminently venomous or Viperine group, as for instance, the 
rattlesnake, &c. In the poisonous serpents belonging to the 
Colubrine group, as the cobra de capello, &c., the poison 
fangs are fixed, and are not movable. ISee — Cobra. 
