SINCLAIR: MARSUPIALIA OF THE SANTA CRUZ BEDS. 355 



its articular surface on the trapezium, it was larger than in Thylacynus. 

 The second metacarpal overlaps proximally the third, and the fourth 

 on the fifth. The proximal end of the third has not been preserved. The 

 fourth is the longest element in the metacarpal series. Its proximal end 

 is irregularly quadrangular in outline, wider dorsally than at the palmar 

 margin. The head of metacarpal V is separated by a sharp keel into two 

 convex facets for the overlapping metacarpal IV and the unciform respec- 

 tively. Distally, the metacarpals are flattened, with well-developed keels 

 confined to the palmar surfaces. The arrangement of the phalanges 

 shown in the figure is arbitrary, as there was no possible way to determine 

 the original association of these elements in the matrix. The phalanges 

 of the proximal row are much shorter and heavier than in Thylacynus, 

 with straighter shafts. Those of the second row are less flattened than in 

 the recent genus. The distal trochleae of the phalanges of the first and 

 second rows have no greater dorso-palmar extension than in Thylacynns 

 and there is no reason to believe that the angulation of the digital elements 

 was any greater. The unguals are stout, resembling the claws of Thy- 

 lacynus, but differing from that genus in the broad Assuring of the tips. 

 The subungual processes are large. Hoods are developed to about the 

 same extent as in Thylacynus. An ungual foramen is present in all the 

 claws. 



In proportion to the size of the skull, the femur (PI. XLVI, figs. 3, 3*7) 

 is remarkably short. The head is of about the same size as in Thylacynus, 

 but the neck is considerably longer. The great trochanter projects slightly 

 above the level of the head, from which it is widely separated. The lesser 

 trochanter is incompletely preserved, but was probably as large propor- 

 tionately as in Frothy lacy nus. The shaft is straight. The condyles are 

 narrower antero-posteriorly than in Thylacynus and are plane or slightly 

 convex transversely. The inner condyle is considerably wider than the 

 outer. 



Restoration (PI. LXI, fig. 3). The disproportionately large size of the 

 head and great length of the neck are at once apparent in the drawing of 

 the restored skeleton. The length of the back has been determined by 

 comparison of the lengths of the few dorsals preserved with the corre- 

 sponding parts in Thylacynus. The lumbar vertebrae and pelvis are sup- 

 plied from Prothylacynus. The length of the tail is largely hypothetical, 

 but the size of the proximal caudals indicates that it was greatly thickened 



