Digestive System Special. 85 



ber and the Molars of a more uniform and simple structure. 

 Situation. In tlie Dasyuridae the points of the lower Canines are 

 received in hollows of the interraaxillarj palatal plate, and do not 

 project, as in the Sectorialia, beyond the margins of the maxillary 

 bones. In the Myrmecobiidse the inferior Molars are directed 

 obliquely Inwards, and the whole dental series describes a slight 

 sigmoid curve. Form. All the Incisors in the Myrmecobiidae are 

 slightly compressed diudi pointed. In Phascolomydse and Macropidae 

 they have persistent pulps. The anterior tooth of the Molar series 

 in Hypsiprininus has a peculiar trenchant form, indented especially 

 on the outer side, and in young teeth, by many small vertical grooves. 

 In the Phascolomyda3 the false and true Molars have persistent pulps, 

 and are consequently devoid of true fangs, in which respect the 

 "Wombat diifers from all other Marsupials, and resembles the denti- 

 gerous In-Enamellata and herbivorous Rodentia. The Premolars of 

 the Macropidae are distinguished by being compressed, and narrower 

 in front than behind, having two cusps behind and one in front. In 

 the omnivorous Peramelidae the Molars (originally quinque-cuspi- 

 date) early assume a smooth oblique grinding surface. In the 

 Myrmecobiidae the Molars are multicuspidate. 



Mbnotremata. In Echidna teeth are wanting. In Ornithorhyn- 

 chus two horny plates, consisting of a series of close-set vertical 

 hollow tubes, and situated on each side of each jaw, eight in all, 

 serve for teeth : the anterior pair, above and below, are narrow and 

 somewhat trenchant, the posterior pair are subquadrate and slightly 

 tuberculate, each tubercle being separately developed, and becoming 

 confluent with its fellows in the course of growth. (For lingual 

 teeth, see above, p. 72.) 



12. The Phanjnx. 



Ferissodactyla. In the Horse the Pharynx is capacious and com- 

 municates with a pair of large sacculi at the ends of the Eustachian 

 tubes. 



Artiodactyla. In Giraffa the back part of the mouth terminates 

 by a transverse slit, through which projects the broad upper margin 

 of the Epiglottis, which is folded upon itself. 



In-Enamellata. In Dasypus (Q. Cinctus) the Epiglottis projects 

 through the arch of the Soft Palate. 



13. The (Esophagus. 

 is short and wide in all Sectorialia. 



