326 



COMPARATIVE ANATOMY 



In marine Chelonians and Crocodiles there are no large glands 

 united into groups connected with the mouth, but in Testudo 

 gneca there are well developed sublingiial glands. 



Pterygosphenoidalis Pterygo- 



ant. parietalis 



i 



Retractor quadrati 



Maxilla 



Fang 



Quadrate 



Pterygosphen- 

 oidalis post. 



Mandible 



Transveo-maxillo 

 pteryyo-mandibula 



B 



Maxilla 



Palatine L -j 



Pterygoid - 



Duct oj poison-gland 

 Fang 

 - Zygomatic ligament 



-Poison-gland and sheath 



x \\X\\iYVJf \ A^\.l'\l I' xM. 



Ptert/gosphcnoidalis post. 



-" Masticatory muscles 

 ~~ Ziigomatic ligament 



Mandible 



Portion oj trans.-inax.-pter.-nw.nd. muscle 

 FIG. 238. HEAD OF THE VIPER (after Katheriner). 



A, from the left side : the integument, zygomatic ligament, poison-gland, jaw- 

 muscles, and palatine and pterygoid teeth are not indicated. B, left side 

 from below : the muscles of the jaw are cut through transversely, and part 

 of the sheath of the poison-gland is slit open. 



Birds. --In Birds, and more especially in climbing Birds 

 (Scansores), a well-developed lingual gland is present opening on 

 the floor of the mouth, and another at the angle of the latter. 



