46 ON THE rnTSIOGNOMY 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 otlier lobes, smaller but co- 

 herent. 



The lacliri/mal gliind 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.-|- When 

 it exists, it occupies the f renal 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 lachr}anal gland. This gland is very large in 

 the Xenopeltis, in some of the Colubri, and in the Trigo- 

 noceplialus 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 3fus., vol. vii. p. 62. 



t The learned Professor MiiLLER was the first to discover its exist- 

 ence in Ophidians. See Meckel, Archiv., Am. 1829, p. 70. 



