AND TEETH OF THE OPISTHOGLYPHA. 



309 



(text-fig. 8). Of the more highly-developed parts the parotid 

 gland and the posterior tooth aie most striking. The gland ip.g.) 

 is quite well developed, and it extends far behind, as far as the 

 angle of the jaw, and in front up to the middle of the eye, while 

 in shape it is peculiar in being rectangular ; in fact, as will be 



Text-figiu'e 10. 



P9 



Tropidonotus stolatus. Dissection of head from the left side. 

 Letters as hefore. X 6. 



seen from the diagram (text-fig. 10), more than half the glandular 

 area in the region of the maxilla has taken up the function of the 

 secretion of the serous fl.uid. Apart from its great development 

 in size, the dissection shows that the parotid gland is really a part 

 of the superior labial gland, and is only to be distinguished from 

 it by its yellow colour. 



Text-figure 11. 



Tropidonotus stolatus. Longitudinal section of the head in the region of the 

 poison fang and duct of parotid gland. /. fang ; duct p.g. duct of poison 

 or parotid gland ; op.t.s. opening of duct into tooth sac ; r.t. reserve tooth ; 

 ves. vestibule. X 63. 



The maxilla bears about eighteen teeth, these being svibequal 

 in size, except the last. This (/) is much increased in size, and 

 is more than twice the length of the tooth in front of it. It is 



Proc. Zool. Soc— 1923, No. XXI. 21 



