46 
Q-N THE PHYSIOraOMY OF SERPENTS. 
one structure, present differences among themselves in 
aspect and figure. The nasal, for example, is more hard 
to the touch than those of the jaws ; the lachrymal gene- 
rally exhibits a smooth surface of a paler colour and softer 
consistence than the rest ; and the maxillary glands, when 
they have a very large posterior lobe, have sometimes 
that portion subdivided into other lobes, smaller but co- 
herent. 
The lachrymal gland sends, according to the observation 
of M. J. Cloquet,^ a part of the fluid it secretes into the 
cavity before the ball of the eye. In this respect it is a 
true lachrymal gland ; but its large size, in some serpents 
with very small eyes, and the circumstance that the super- 
fluous secretion is poured by several small excretory canals 
into the mouth, leads to the supposition, that it performs 
the double office of a lachrymal and salivary gland, and 
that in some Ophidians it probably merits the latter de- 
signation more especially. It is constantly found in all 
Ophidians ; it is placed behind the eye-ball, protected by 
the posterior frontals when they exist, and is often covered 
by the temporal muscle ; while, in other serpents, it is more 
or less completely buried in the orbit surrounding the pos- 
terior border of the eye. 
A nasal gland is found in most Ophidians. “f" When 
it exists, it occupies the frenal region, and reaches the 
back of the nostrils. M. Muller has found that it pours 
its secretion into the mouth by an excretory duct joining 
that of the lachrymal gland. This gland is very large in 
the Xenopeltis, in some of the Colubri, and in the Trigo- 
nocephalus Rhodostoma. 
The salivary glands of the jaws are much less developed 
in venomous than in innocuous snakes. There are but 
few species of the latter tribe which have them small, but 
the Eryx is totally without maxillary glands. The species, 
on the contrary, with grooved or long posterior maxil- 
lary teeth, have always a large gland in that region, which 
is sometimes more or less separated from the rest of the 
^ Mem. du Mus.^ vol. vii. p. 62. 
t The learned Professor Muller was the first to discover its exist- 
ence in Ophidians. See Meckel, Archiv., Am, 1829, p. 70. 
