AND TBETH OF THE OPISTHOGLYPHA. 



311 



to its teeth and glands. The parotid gland {p.g.) in this snake 

 is much enlarged, and its extension forward goes much further 

 than in Tropidonohis, almost to the anterior end of the maxilla. 

 Behind, it extends further than the angle of the jaw, and ends 

 almost on a level with the superior labial gland ; in fact, it has 

 taken up so much of the glandular area that the superior labial 

 gland is left reduced to a mere strip of glandular mass, which in 

 dissection has an appearance more or less like that of the poisonous 

 snakes. The lobules of the gland are larger than those of the 

 superior labial gland. This is the only case I have yet met with 

 in aglyphous or opisthoglyphous snakes where the poison gland 

 is so highly developed and extends further forward than the 

 middle of the eye. The most interesting feature to notice is the 

 point of termination of the gland in front ; it gradually narrows, 

 and ends with a little bend above the enlarged fang-like tooth, 

 appai'ently giving an impression in dissection of the duct of 



Text- figure 14. 

 f P9- 



Lycodon aulicus. Dissection of head from the right side. Letters as before. X 6- 



proteroglyphous snakes opening at the base of the fang. I 

 hope at some future time, when more material is available, to 

 make a moi-e complete examination of the anterior end of the 

 jaw of Lycodon, in order to put to the test Boulenger's sugges- 

 tion of the probable evolution of the Proteroglypha from the 

 Aglypha. 



There are eighteen maxillary teeth, the anterior three are large 

 and are followed by a diastema, the next fourteen are very small, 

 and the last two are large and fang-like, and are enclosed within 

 a muscular tooth sac similar to that already noted in Tropido- 

 notus. In the transverse section (text-fig. 15) of the head of 

 Lycodon will be seen the section of the posterior tooth sac 

 (/". & t.s.). It will be noticed that the tooth is further spe- 

 cialised than that of Tropido7iotus by the growth of cutting-edges 

 on both sides. These cutting-edges §,iye the appearance of a 

 lancet. 



21* 



