302 MU. S. C. SARKAR ON THE BUCCAL GLANBS 



front face of the tooth or on the external surface. In. some cases 

 the groove slightly curves round in its course ; it may extend 

 throughout the length of the tooth or may end a little above the 

 tip. The groove may be shallow^, or may be widely open or 

 almost closed. 



Morphological Description of the Dissection of the Heads 

 of afeto Opisthoglyphous Snakes. 



Genus Dryophis. 



Dryophis mycterizans. (Text-fig. 19.) 



The poison gland is distinctly definable from the superior 

 labial gland, and is large and extends a little further forw^ard 

 than the middle of the eye and posteriorly a little behind the 

 angle of the jaw. The superior labial gland reaches to the 

 anterior extremity of the maxilla, and it extends a little behind 

 the poison gland. The two portions of the gland are continuous 

 with one another. Near the region of the fang-like tooth in 

 front the gland becomes broader. The inferior labial gland 

 consists of a very thin strip of glandular tissue, and does not 

 extend as far as the angle of the jaw. There are fourteen teeth 

 altogether in the maxilla, and they are arranged as follows: — 

 four small teeth in front, then two large fang-like teeth, followed 

 by a diastema, then six very small teeth, and finally two very 

 large, stout, and straight grooved teeth. The groove is on the 

 outer side and is deep and extends throughout the length of 

 the tooth. The duct of the poison gland opens near the base of 

 the tooth. There are eighteen teeth in the mandible. The 

 first is rather small, the next three very large, the middle of the 

 three being the largest, then a diastema, which is followed by 

 fourteen teeth which gradually diminish in size. The Harderlan 

 gland is much reduced, and consists of a thin strip of tissue lying 

 behind the eyes in the eye-socket. 



Genus Cerberus. 

 Cerberus rhynchops. 



The poison gland is clearly distinguished from the upper 

 labial gland, and is large and oval (text-fig. 5) ; it is so distinct an 

 organ that it can be easily picked up from the surface of the 

 superior labial gland without injury to the latter. The superior 

 labial gland extends from the anterior end of the maxilla and 

 posteriorly up to the poison gland. Practically the whole of the 

 posterior portion of the glandular area is occupied by the poison 

 gland, so that the superior labial gland does not extend far 

 behind the eye. The lower labial gland also does not extend up 

 to the angle of the jaw ; this is probably due to the sharp 

 upward turning which the lower jaw takes, thus giving a greater 



