0 
THE THANATOPHIDIA OF INDIA. 
American congeners, sucli as tire Crotalus horridus, or Kattle- 
snake, the Jararacca, or Craspedoceplialus braziliensis, which are 
much more deadly than any of the Crotalidse of this country. 
The four poisonous families are:— 
Elapidse. 
Hydrophidse. 
Viperidse. 
Crotalidaj. 
Coluhrine. 
Viperine. 
The seventeen innocuous families are 
1. Typhlopidse. 
2. Tortricidse. 
3. Xenopeltidse. 
4. Uropeltidse. 
5. Calamaridse. 
6. Oligodontidse. 
7. Colubridse, 
8. Homalopsidse. 
9. Psammophidse. 
The four poisonous families contain :— 
10. Dendrophidae. 
11. Dryiophidse. 
12. Dipsadidse. 
13. Lycodontidse. 
14. Amblycephalidse. 
15. Pythonidse. 
16. Erycidse. 
17. Acrochordidse. 
Genera. 
Elapidae.5 
Hydrophidse.4 
Viperidse.2 
Crotalidge.4 
15 
The cranium of a snake is built up of a number of bones 
which have their homologues in the Mammalian skull, but are 
more complex, and modified in accordance with the structure 
and habits of the reptile. It is unnecessary to describe, in 
detail, the bones which enter into the formation of the cranial 
cavity, which is very small, being in proportion to the imper¬ 
fectly developed encephalon it protects. But as those which 
enter into the structure of the maxillary and mandibular arches 
are of importance in distinguishing the venomous from the 
non-venomous snakes, it is well that a short description of them 
should he given. It is the peculiar structure of the jaws, 
indeed, that forms one of the chief characteristics of the 
Ophidians. The bones which compose the upper jaw and 
palate, as well as the mandibles, are freely moveable, the latter 
being loosely hung from the tympanic hones, and are united 
in front by ligament. The mastoid hones with which the 
tympanic bones articulate are also moveable, so that the dis- 
tensibility of the mouth is very great, as it often needs to 
he, to enable the snake to swallow prey larger in diameter than 
itself. 
The mechanism of deglutition in the Ophidia is very remark¬ 
able ; the mouth can not only he opened vertically, hut trans¬ 
versely, and further, each lateral half has the power of separate 
and independent motion which is called into action when the 
prey is swallowed. By the continual action of the jaws and 
teeth, the animal brought within the grasp of the mouth, is 
slowly drawn in and engulfed; it is first held firmly by the 
sharp recurved teeth, one side of the jaw is then protruded, the 
teeth being withdrawn to be again implanted further on ; the 
same process is repeated alternately on either side, until the 
prey is finally drawn within the grasp of the gullet. This is 
the mode of deglutition in the Python and other non-venomous 
snakes. A similar process, with certain modifications in the 
dental arrangement, obtains in the poisonous snakes; the chief 
structural distinction being found in the maxillary teeth, which 
in them are long, sharp, recurved, and perforated fangs, through 
which the secretion of the poison gland is hypodermically 
injected into the bitten animal. Before describing the maxil¬ 
lary arch, it may he well to say a few words about the dentition 
of serpents generally. The non-venomous forms have two 
rows of teeth in the upper jaw: the outer or maxillary, the 
inner or palatine. In the majority, the outer row has from 
twenty to twenty-five teeth, though in some genera, as Tortrve, 
Ilornalojjsis, the} r are less numerous ; in the typical venomous 
snakes the maxillary hone is very short, and the outer row is 
represented by a single long tubular fang, which is firmly 
anchylosed into the moveable maxillary hone, with loose reserve 
fangs in the mucous fold surrounding it. In other genera, 
Dryioplns, Dipsas, the maxillary teeth increase in size towards 
the posterior part of the bone, and the terminal teeth are even 
grooved on their convex surface ; these teeth may enable the 
snake to retain a firm hold on its prey, or they may give entry 
to acrid saliva, hut they are not connected by a duct with any 
poison gland. 
The grooved or perforated poison fangs are firmly fixed in 
the maxillary bone, and are covered by a fold or capsule of mu¬ 
cous membrane, in which they are ensheathed, and in which 
several reserve poison teeth, in different stages of growth, lie 
loose until one of them is called for by the loss of the 
actual fang. Its successor then becomes anchylosed to the 
maxillary hone, and communicates with the duct of the poison 
gland. 
The teeth of the Ophidia generally are conical, sharp pointed, 
and recurved weapons, firmly fixed in the hones with which 
they are connected. In some snakes the pre-maxillary, or inter¬ 
maxillary hone is without teeth ; in others it is furnished with 
them. The maxillary hones, in the poisonous snakes, have one 
or two grooved fangs, one only of which on either side is 
effective ; and in some of the poisonous coluhrine snakes, 
as Cobra or Bungarus, there may be one or more smaller teeth 
of the ordinary kind immediately behind the poison fangs. 
In the non-venomous coluhrine snakes the maxillary bone has a 
whole row of equal sized recurved teeth. This rule, though 
general is not absolute, for some snakes have fangs although 
they are not venomous. Gunther says of the Psammodynastes 
pulverulentus :—“ This snake has a very repulsive aspect: its 
dark, undefined colours, short and thick head, and swollen lips, 
caused by large hidden fangs, give it the appearance of a veno¬ 
mous snake ; it remains small, the largest specimen I have seen 
being only 21 inches long, the tail measuring 4^ inches. It 
has a wide geographical range, occurring in Ivhasya, Sikkim, 
Assam, Begu, M^ergui, Cochinckina, Sumatra, Java, and the 
Philippine Islands. ” There are some good specimens in the 
Indian Museum lately presented by Major Godwin Austen 
from the Ivhasya hills. The long fangs are distinctly marked, 
and the snake looks very much like a venomous one. The 
palatine teeth are of about the same size as the maxillary 
in non-venomous snakes. The pterygoid teeth are somewhat 
smaller. 
A diagram of the dentition of the Ptyas or Dhamin would be 
as in Figure 1 ; of the Cobra, or of the Bmgarus as in Figure 2; 
of the Daboia or Yiper as in Figure 3. 
Dhamin [Ptyas mucosus). 
Naja tripudians. 
Daboia russellii. 
Innocent Snake. 
Cobra. 
Viper. 
Figure 1. 
Figure 2. 
Figure 3. 
•. \ 
® • « 
& • • ® 
The dotted lines show the directions of the marks that would he made by the bites of— 
1. Diiamin. 2. Cobka. 3. Daboia kusseliii. 
The actual number of maxillary, palatine, and pterygoid teeth is not indicated by the marks, 
blit merely the direction they take. 
In the Viper they are not much above 8 or 10 palatine or pterygoid, only one maxillary. 
In the Cobra 25 or 26 pterygoid or palatine, and one, or perhaps a second, small (though not 
a poison fang) maxillary. 
In the Ptyas (Dhamin) or harmless snake, from 35 to 40 pterygoid or palatine teeth, and 
to 22 maxillary teeth. 
