98 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XIV. 



The features which seem most noteworthy, although of widely vary- 

 ing significance, are the following: 



1 . Atlas with open grooves or notches instead of closed foramina 

 for passage of cranial nerves and vertebral arteries; agreeing 

 only with Perameles, Marmosa, and Peramys. 



2. Axis with movable cervical rib; agreeing only with certain 

 species (or individuals?) of Perameles and Phascologale. 



3. Seventh cervical tending to become imperf orate; inter- 

 mediate between diprotodonts and polyprotodonts. 



4. Spine of first thoracic vertebra scarcely exceeding that of 

 last cervical but greatly exceeded by that of second thoracic; 

 agreeing only with Perameles. 



5. Vertebral spines converging to a center of motion; disagree- 

 ing with Didelphiidae. 



6. Costal element of first rib longer than vertebral; agreeing 

 only with Trichosurus and Petaurus. 



7. Ventral surface of xiphisternum not continuous with that of 

 mesosternum; agreeing only with diprotodonts. 



8. Pubic symphysis exceedingly short; unique among mar- 

 supials. 



9. Ischial rami not flaring. 



10. Marsupial bone with very long base; unequalled among 

 marsupials. 



11. A large heavy humerus combined with a relatively slender 

 forearm; unique among marsupials. 



12. Trochlea of humerus extended inward to form a partially 

 separate articular surface; unique among marsupials. 



13. A sesamoid in the supinator tendon at the external epicondyle 

 of the humerus; unique among marsupials. 



14. Radius flexed forward in its proximal third, in contact with 

 ulna distally; agreeing with saltatorial or semi-saltatorial 

 forms. 



15. Pisiform large, relatively larger than in other marsupials 

 examined. 



1 6. Patella ossified; agreeing with Perameles, Notary ctes and 

 Tarsipes; also with extinct forms Amphiproviverra and Pro- 

 ihylacynus. . 



17. Femur with a rudimentary third trochanter; agreeing only 

 with Phascolomys and Wynyardia. 



1 8. Tibia and fibula relatively long and in close contact distally; 

 agreeing only with saltatorial forms. 



19. Internal malleolus of tibia large ; agreeing with Macropodidae. 



