878 DR. C. F. SONNTAG ON THE VISCERAL ANATOMY 



rugse. Duodenal loop difFerentiated. Caecum well-developed. 

 Spleen massive and triangular. Thyroid gland posterior. 

 Mammae symmetrical. Patella ossified. Mammae 6-8. 



Sub-order DIPROTODONTIA. 



The Dij^rotodontia have few characters common to all their 

 genera in contradistinction to the Polyprotodontia. And these 

 characters are : — Parotid glands large. Tongue has reduction in 

 the sublingua and shows lateral organs. Thymus gland has 

 two cervical and two thoracic lobes. Meckel's Tract long. 

 Caecum large. 



Familj'^ Macropodid^e. 



Characters common to all Genera : — Lips cleft. No cheek- 

 pouches. Oral vestibule ridged. (Esophagus has no transverse 

 rugae. Stomach sacculated. Lungs have small degree of 

 division. Vagus and sympathetic nerves separate. Thyroid 

 gland anterior and has no isthmus. Mammae symmetrical. 

 Patella not ossified. 



Genus Macropiis : — Both labial frenums present. Palatal 

 formula C^I(,P-)-XJ— . Epiglottis notched and wide. Spleen 

 with lateral process. Stomach has patches of follicular glands 

 and the a,rea of digestive epitheliuixi is small. CEsophagus enters 

 stomach near cardiac end. Mammre 4. 



Genus Dendrolagus : — Large labial tubercles. No lower labial 

 frenum. Palatal formula CJoP + U — . Epiglottis entire and 

 folded. Stomach with large area of digestive epithelium and 

 follicular glands in patches or strips. Spleen Y-, T-, or 

 spoon-shaped. Esophagus enters stomach near cardiac end. 

 Mammae 4. 



Genus ^Epyiirymnus : — No labial tubercles. Both labial 

 frenums present Palatal formula C.IoRU — . Epiglottis wide 

 and notched. CEsophagus enters stomach near pyloric end. 



Family Phalangerid^. 



Characters common to all Genera : — Lips entire. No cheek- 

 pouches. Ql^sophagus has no transverse rugae. Stomach simple 

 and has no special gland. Duodenum not a very specialized 

 loop. Meckel's Tract short. Caecum well-marked. Mammae 

 symmetrical. Patella not ossified. 



Genus Petatirus:- — No labial tubercles. Both labial frenums 

 present. Oral vestibule smooth. Palatal formula varies. Epi- 

 glottis entire and rounded. Spleen an isosceles triangle. Vagus 

 and sympathetic fused. Mammte 4. 



Genus Pseiidochirus : — Lower labial frenum absent. Lai'ge 

 labial tubercles. Oral vestibule ridged. Palatal formula 

 CgloP — U— . Epiglottis entire. Vagus and sympathetic sep- 

 arate. Mammae 4. 



