SINCLAIR: MARSUPIALIA OF THE SANTA CRUZ BEDS. 385 



similar to that in Prothylacynus (PI. XLIX, fig. 4). The internal malleolus 

 is prominent. 



The fibula (PI. LVIII, fig. 9) is intermediate in shape between that of 

 Prothylacynus and that of Thylacymts. Proximally, it is flatter than in the 

 former genus, having the facets for the tibia and lateral sesamoid relatively 

 longer. The shaft is curved sigmoidally, supporting a strong interosseous 

 ridge. Distally the shaft becomes roughly circular in section. In shape, 

 the articular surfaces for the astragalus and calcaneum are much the same 

 as in Prothylacynus. 



In general, the pes (PI. LIV, fig. 3) resembles that of Dasyurus macu- 

 latus. The trochlear surface of the astragulus (PI. LIV, fig. 10) is not as 

 flat as in Amphipro'vi'verm and Prothylacymts and is somewhat narrower 

 proportionately than in the latter genus. The tibial portion is not pro- 

 duced distally on the dorsal surface of the neck, as in Prothylacynus. 

 The articular surfaces on the plantar aspect are substantially the same as 

 in the last-mentioned genus (cf. PI. LIV, fig. 2.0]. The calcaneum differs 

 from that of Amphipromverra in lacking the deep groove for the accom- 

 modation of the calcaneo-cuboidal ligament. The relative position of the 

 tarsals is the same as in Prothylacymis. The cuboid lacks the notch in 

 its dorsal border between the articular surfaces of the fourth and fifth meta- 

 tarsals, which is so noticeable a feature in both Prothylacynus and Atnphi- 

 proviverra. The shifting of the external cuneiform toward the outer side 

 of the foot has progressed to about the same extent as in Prothylacynus. 

 The hallux is not preserved, but from the small cup-shaped character of its 

 articular surface on the entocuneiform, it is probable that it was propor- 

 tionately no larger than in Dasyurus maculatus or D. viverrinus, having 

 lost the opposable condition retained by Amphipro'vi'verm. The meta- 

 tarsals interlock proximally and spread apart distally. Their distal ends 

 have been destroyed in the right pes represented in the figure, but are well 

 enough preserved in the left pes to show that the fourth is the longest, an 

 arboreal character (Dollo, 1899 ; Bensley, 1903) retained alsojin the manus, 

 where, it will be remembered, the pollex is large and opposable (cf. PI. 

 LIV, fig. 4). 



Restoration of the Skeleton (PI. LXI, fig. i).- -The lack of proportion 

 between head and body, which has been so often referred to in the discus- 

 sion of the Santa Cruz thylacynes, is nowhere more marked than in Clado- 

 sictis. The lengths of the few missing dorsal vertebrae were determined 



