Digestive System Special, 69 



Artiodactyla. The mouth of the Hog tribe has the upper h'p 

 and nose modified to form the * snout.' 

 Do not always form entire segments of an ellipse. 



Cheiroptera. In !N"3'cteris the two converging ridges of the lower 

 lip enclose a triangular prominence of the upper lip. 



Hodentia. In some Hodentia the upper lip is partially cleft. 



Proloscidia. In Elephas the under lip is produced into a pointed 

 form. 



Artiodactyla. In the Camelidae a mid-fissure divides the upper 



lip- _ \ 



Marsupialia. The upper lip is partially cleft in the Macropidse. 



3. Gape of the Mouth. 



Cheiroptera. Those species that feed on insects have a very wide 

 gape. 



Sectorialia. The mouth is characterised by the width of its gape. 



In-Enamellata. In the Edentula (Myrmecophagidae) the long 

 and tubular mouth seems to serve mainly as a sheath for the slender 

 tongue when retracted. 



Monotremata. The mouth of Echidna is long and tubular, as in 

 the Ant-Eater, and terminates by a small orifice. 



4. Cheeh Pouches. 



Quadrumana. Cheek Pouches are never found in the highest 

 Apes. But in the lower Catarrhina, and in these alone of this 

 Order, they are found. 



Rodentia. In Cricetus (Hamster) the wide orifice of the pouch 

 is just within the commissure of the short lips : the bag itself ex- 

 tends along the side of the head to the neck. In Saccostomus it 

 reaches back as far as beneath the ear. 



Sectorialia. Cheek pouches have not been found in any species. 



Marsupialia. A few species have Cheek Pouches. In Koala 

 they are wide and shallow. In Didelphys Yapock they are large. 



Mofiotremata. Ornithorhyncus has an oblong Cheek Pouch, in 

 which it may stow away fresh water Insects, Crustacea, &c. 



5. Buccal Memhrane. 



Artiodactyla. In the Euminantia the cavitj' of the mouth is 

 lined with retroverted papillse. 



In-Enamellata. In Myrmecophaga the Buccal membrane rises in 



