410 
SPANISH -TOWN. 
These are valves that shut in the throat. We are led 
to conclude on first seeing these valves that we 
are examining an animal that has no tongue, and 
that the underfold of what we are inspecting is the 
rudimentary trace of that member cut out. This, 
however, with the corresponding curtain above it in 
the roof of the mouth, forms an apparatus that closes 
the distending aperture of the throat, and permits 
the reptile to hold its prey and drown it, without 
being itself liable to be drowned. 
“ Between the branches of the lower jaw, a certain 
degree of muscularity is perceived in the yellow floor- 
ing of the mouth. This is the representative of the 
tongue. The thickened membrane shows its lingual 
analogue, though destitute of all approach to a red 
colour, by its rough glands and pores giving out 
saliva. 
The nostrils, placed at the extremity of the snout, 
terminate in a post-oral cavity, by passages that com- 
municate with the throat behind the valvular appa- 
ratus we have been describing. This is a provision 
for respiration when the valves are closed, which at 
once renders intelligible and necessary a remarkable 
structure of the fauces by which the upper jaw seems 
to move upward, whilst the under one retains its 
horizontal position. The lower is prolonged behind 
the skull to a great depth. On raising the head at 
an angle, the upper jaw appears to move upward, and 
the under jaw to remain immovable. The upper 
jaw does indeed move upward, but not independently. 
On casting back the head, an acetabulum of the 
united skull and jaw acts on a condyle of the lower 
