SINCLAIR: MARSUPIALIA OF THE SANTA CRUZ BEDS. 399 



appears to have been proportionately larger than in Sarcopliilns or Tliy- 

 lacynus. As in Cladosictis, this surface is divided by a sharp keel into a 

 small inner and a large outer rotular groove, indicating an enlargement of 

 the outer condyle of the metacarpal, which produced a deflection of the 

 phalanges of the pollex toward the inner side of the foot. The remaining 

 proximal phalanges are short and stout, with straight shafts and prom- 

 inent tuberosities for the annular ligament. The distal trochleae are 

 without trace of the median keel-like structures observable in Sarcopliilns, 

 resembling in this respect Thy lacy mis. The proximal articular surfaces 

 of the phalanges of the second row are prolonged dorsally by the devel- 

 opment of tongue-like processes fitting between the condyles of the prox- 

 imal phalanges, indicating that these two sets of elements were carried 

 with respect to each other at a considerable angle. The unguals are la- 

 terally compressed, sharp-pointed and without terminal clefts. Hoods are 

 developed to about the same extent as in Sarcophilus and Dasynrus 

 maculatus. 



With the exception of the claw of the second digit, the figure (PI. LIV, 

 fig. 5) shows the original association of the phalanges of the manus. The 

 ungual interpreted as that of the second digit lay in the matrix above the 

 fifth metacarpal. 



In the pes (PI. LIV, fig. 6), the trochlear surface of the astragalus is 

 short and almost flat transversely. Distally, the tibial trochlea is pro- 

 duced on the upper surface of the neck. The neck is proportionately 

 longer than in Sarcophilus and Thylacynns and the head is less obliquely 

 placed than in those genera. The calcaneal and sustentacular facets are 

 like those of Prothylacymis (PI. LIV, fig. 20) in shape and position. Two 

 minute astragalar foramina are present. The calcaneum has the tubercle 

 for the attachment of the calcaneo-cuboidal ligament greatly enlarged and 

 grooved. The calcaneum carries a facet for articulation with the fibula, 

 which is confluent with the ectal facet for the astragalus. The susten- 

 tacular facet is concave and is broadly separated from the former, unlike 

 the condition in Sarcophilus and Thylacynus. The tuber calcis is rela- 

 tively shorter than in those genera, occupying somewhat less than one 

 half the total length of the calcaneum. The remaining tarsals agree 

 closely in shape and in the arrangement of the articular facets with those 

 of Protkylacynus and do not call for separate description. 



The hallux, when brought into articulation with the entocuneiform, is 



