38 1 
ME. CHAELES S. TOMES ON THE DEVELOPMENT AND 
Description op the Plate. 
PLATE 37. 
The same lettering applies to all the figures. 
1. The poison-fang at present in use. 
2 . The tooth which stands next in order to replace the one in use. 
3. The third in order of succession, &c. 
a. Epithelium of the mouth. 
a'. Epithelium continued into the pouch. 
1). Connective-tissue septum, which serves to keep to their respective sides the 
teeth of the two parallel series when they move into position. 
c. Section of pouch of mucous membrane which covers in the poison-fangs whilst 
recumbent. 
d. Formed dentine. 
e. Enamel-cells of the enamel-organ. 
d. Enamel-cells in the groove which is to become the canal for the conveyance 
of the poison. 
f. Process of epithelium passing beyond the youngest tooth-germ, from which 
the next enamel-organ will be formed. 
g. Band of epithelium connecting the tooth-germs with the epithelium of the 
surface. 
h. Space in which the poison-fang lies whilst at rest. 
k. Coarse “ bone of attachment.” 
vi. Maxillary bone. 
n. Transverse bone. 
$>. Dentinal pulp. 
Fig. 1. From English viper. 
Transverse section of poison-fang and its nine successors. The tooth in 
use (i) is on the point of being replaced by a successor ( 2 ), which has already 
passed from the region in which it was developed into the cavity of the 
pouch. Between the two lies the connective-tissue flap, which helps to guide 
it into place, to keep it to its own side, and to keep it straight. Beneath 
these two teeth are eight successors arranged in pairs in two parallel series, 
the new tooth being taken alternately from either side. 
On the right (f) is a process of epithelium from which a new enamel-germ 
would be formed ; the corresponding epithelial process of the left-hand series 
of teeth is not clearly visible. 
The .position of this and some of the other sections will be better understood by a 
reference to the woodcut, fig. 12 (p. 382). 
