132 
MAGAZINE OF SCIENCE AND ART. 
ridr' of which is a large foramen (Fig. 8 , a.) for the 
transmission of the vessels and nerves to each of 
the anterior fangs, and probably also to the poste¬ 
rior rudimentary fangs j upon the inner side, the 
body terminates in a more or less rounded portion 
of bone (Fig 4, d.), projecting' backwards. The 
upper surface of the body varies much in character 
and form ; in the highly poisonous snakes it con¬ 
sists of a Hat articulating surface, the entire width 
of the bone, which, in such a specimen, is always 
broad j this surface (Fig. 8 , 6 .) is perfectly flat 
laterally, hut slightly concave antero posteriority ; 
the concavity being greatest in the least poisonous 
serpents. It articulates with a corresponding 
surface of the malar bone. The under 
surface (Fig( 4, c.) of the body is irregularly 
concave, and possesses an external and anterior 
semilunar strong alveolar ridge of bone (Fig. 4,/.), 
behind the anterior portion of which are two deep 
fossa; (Fig. 3, 4, a. a.); in one of them (generally, 
but not invariably, the external), the fixed or func¬ 
tional fang is placed; the inner fossa is equally 
capacious, but wants the posterior wall of bone 
forming the posterior alveolar ridge, and which is 
only developed when the supplemental fang be¬ 
comes fixed, upon the shedding of the functional 
fang, and, probably, also its accidental fracture. I 
have not met with any specimen possessing two 
fixed fangs in one maxillary bone-, — the posterior 
portion of the floor of the body (Fig. 4 and 5, g.) 
upon this surface, is freely concave, and forms a 
capacious fossa, in which the rudimentary fangs lie 
fully protected. 
Projecting from the external posterior end of the 
body is the ramus (Fig. 3,4,5, e. e. e.), which passes 
backwards, and possesses an anterior neck (Fig. 3, 
8 , d. cl.), short in the venomous, longer in the inno¬ 
cent varieties. Behind this is the dental body (Fig. 
3 , 4 , 5 , e. e. e .); this possesses the same variations 
of form, to a greater extent, in the most deadly 
varieties, carrying no teeth •, in the comparatively 
inocuous, as many as eight. The posterior extre¬ 
mity (Fig. 4, h.) articulates with the pteregoid bone; 
The motion to which this bone is liable consists only 
of an antero-posterior horizontal movement, which 
is of course conveyed to the functional fang, and 
s caused by the action of the great retractor mus¬ 
cle through the pteregoid hone. It is generally 
stated that the maxillary bone can be moved for¬ 
ward in anger, and by such a movement erect the 
fang, which, when retracted into the gum, is suffi¬ 
ciently horizontal not to pierce or interfere with 
the passage of the food into the mouth; but this it 
will be my duty to prove is not the case. 
The pteregoid bone (Fig. 2, c.) is small, irregular, 
and oblong in shape; it articulates anteriorly with 
the posterior extremity of the superior maxillary 
bone, and posteriorly is firmly attached to the retrac¬ 
tor maxillary muscle ; its purpose appears to be that 
of serving as a hinged communication between them. 
In describing the superior maxillary bone, I 
mentioned two dental fossrc, and stated that the 
fixed functional fang was situated in one, and the 
supplemental fang in the other. The former will 
be immediately described, and the latter is, in all 
respects, similar to it, except that the base is not 
fully developed, and occupies but loosely the dental 
fossa ; the fang itself lying recumbent in the loose 
mucous membrane. Behind these, also embedded 
in the loose membrane, are'the two or more rudi¬ 
mentary fangs, in all respects similar in structure, 
though less developed. 
The functional poison-fang is usually fixed in the 
external and anterior fossa of the superior maxil¬ 
lary hone, where it is firmly socketed (Fig. 6, a. a. 
b. b.) in dense bone structure. In form it varies 
but slightly in the various kinds of snakes, but it 
differs greatly in size. A description of one will, 
therefore, be sufficient, and I shall take that of the 
death adder as an example. Fig. 7 represents a 
front view of such a fang, and Fig. 6 the section of 
one, together with its maxillary bone. The fang 
may be described as a long slender tooth, rather 
flattened laterally at the base, round in the lower 
portion, and finely pointed ; it curves gently back¬ 
wards from the base, the point, in some instances, 
turning slightly downwards. Situated anteriorly at 
the base, is a deep triangular fossa (Fig. 7, cl .); 
the apex of which is inferior it is bounded on 
each side by a rounded pillar of dentine (Fig. 7, d.) 
A short distance from the extreme point, also on 
the anterior surface, is a narrow eliptical opening 
(Fig. 7, a. 6, //.), and communicating with these is 
a very slightly depressed line (Fig. 7, b.) In struc¬ 
ture, the fang is composed almost entirely of den¬ 
tine ; and this has been so fully described in 
Professor Owen’s book upon Odontography, that it 
is unnecessary I should enter upon it. The form 
is peculiar, and has given rise to much misconcep¬ 
tion ; but a correct idea of it may be gathered from 
the accompanying drawings. (Fig. 6,!), 10,11,12.) 
It will be seen, that in addition to the pulp cavity 
(Fig. 6 , d; 11 , e.), which occupies the centre of even- 
tooth, a second cavity (Fig. 6,/. 11, d.) exists, the 
entrance to which is at the triangular opening, at 
the base, the c xit being the eliptoid apical 
aperture. (Fig. 7, a.) 
I have spoken of this as a tube, and practically 
it is such, but physiologically it is a groove, the ‘ 
anterior edges of which are closely approximated, 
so effectually indeed, that most writers have consi¬ 
dered it a tubular structure. That it is a groove, 
mechanically closed, is proved by Fig. 6, which was 
taken from a longitudinal section I made a short 
time since. The fang was ground down upon a 
hone, and when so much had been removed, that 
both the triangular and eliptical opening had been 
entered, I was enabled easily to lift off, with the 
point of a fine knife, the intervening thin layer of 
dentine. Fig. 9, 10, 11, 12, also display well the 
grooved tubular character of the fang ; fig. 9 is a 
horizontal section through the triangular opening 
at the base of the tooth; fig. 10, is a section a short 
distance below this opening, and shows the approxi¬ 
mating sides of the tube//; fig. 11, is a section 
from the centre of the fang, where the approxima¬ 
tion of the sides is perfected ; fig. 12, is a section 
made across the upper part of the,apical opening, 
and shows the formation of the aperture to be by 
the separation of the formerly approximated sides. 
The relative proportions of the fangs of all varieties 
of venomous snakes which I have examined, have 
been similar, and the following are those from a 
fair specimen of an adult death adder. 
Length of fang. 3-10 inch 
„ eliptical opening.. 7-500 
Breadth . i 100 
or HORIZONTAL SECTION. 
Breadth outside all. 3-100 
,, anterior posterior .... 3|-100 
poison canal.1|-100 
,, lateral . 1-100 
Thickness of outer wall of dentine, 3-1000 
,, canal.5-2000 
