380 
ME. CHARLES S. TOMES ON THE DEVELOPMENT AND 
to its base, by which it will be anchylosed to the maxillary bone, this process being in 
fact already commenced *. 
The development of poison-fangs in two parallel series, the teeth being arranged in 
pairs of almost equal ages, would suggest that the succession is very rapid and quite 
regular ; were it not so, one would expect to find that the teeth of one series would be 
very markedly in advance of their fellows in the parallel series, which is not the case. 
Moreover the large number of successional teeth (ten) is unusual. I knpw of but one 
other place where more than three teeth can be found in preparation to succeed a single 
tooth, and that place is in the jaws of Ophidia, where six or seven of the ordinary serial 
teeth, in different stages, may sometimes be seen. 
I believe that the development of poison-fangs in two parallel series would be found 
to be the rule, if indeed it be not universal, in viperine poisonous snakes. I can only 
positively answer for the English viper, the puff-adder, and the rattlesnake, these 
being the only poisonous snakes of this group which I have obtained quite fresh. But, 
judging from the vacant spaces by the side of the attached poison-fangs in macerated 
skulls, the arrangement holds good in all viperine snakes that I have seen. 
The region where teeth are being developed in a colubrine venomous snake, the 
Indian cobra, is strikingly different. There is no double series, but the successional 
teeth are disposed in a single series, just like the teeth of a harmless snake, or the man- 
dibular or pterygoid teeth of a poisonous snake. In fact the description which I gave 
in a former paper of the manner in which the teeth of the harmless Ophidia are deve- 
loped would apply strictly to the poison-fangs of a cobra, save only that the individual 
tooth-germs are modified to form canaliculated teeth. 
In fig. 5 there is seen a line of inflected epithelium (g) running in from the oral 
epithelium (a) ; this, which goes to form the enamel-organs of successive germs, is lost 
sight of behind the first successional tooth-germ ( 2 ) ; its free extremity, already slightly 
dilated near where it will form a fresh enamel-organ, is seen at f. The section, having 
been taken a little behind the erect poison-fang already in use, shows no trace of this ; but 
sections including the working tooth do not in the cobra show much of its successors, 
which lie behind it and are recumbent, whilst it is erect. The new tooth occupies 
more nearly the same spot as its predecessor than is the case in the Vipers. 
It is, I think, a legitimate inference that the cobra, having lost one poison-fang, would 
remain unarmed for a longer period than a viperine snake, in which latter the new 
tooth is able to get into place and be ready to be fixed before the loss of its prede- 
cessor. May this not explain the preference shown by the Indian jugglersf for the 
* Dr. Weir Mitchell (“ On the Yenom of the Rattlesnake,” Smithsonian Contributions, 1861) had become 
aware that the succession was regular, and that the new tooth came up by the side of the old one ; he did not, 
however, arrive at a correct interpretation of the positions and movements of the successional teeth as they are 
developed and rise into place. 
t Snake-charmers do, however, sometimes make use of viperine snakes, e. g. the Tic Polonga ( Daboia Russellii). 
