34 6 
PATAGONIAN EXPEDITIONS : PALAEONTOLOGY. 
and both manus and pes are pentadactyl in A mphiproviverra and Clado- 
sictis. 
7. The trochlear surface of the astragalus in the Santa Cruz forms is 
short and flat with feebly differentiated facets for the tibia and fibula. 
This has been interpreted as indicating a plantigrade gait. In the digiti- 
grade Thylacynus the astragalar trochlea is both longer antero-posteriorly 
and more deeply grooved. 
8. There is no trace of syndactyly in either the living Tasmanian or 
extinct Patagonian thylacynes. 
9. The pubes do not appear to have supported epipubic ossifications in 
Cladosictis . In the only specimen of Frothy lac yn us in the Princeton col- 
Fig. 5. 
Thylacynus cynocephalus. a, fifth and sixth lumbar vertebrae from the right side ; b, atlas from 
above ; c, atlas from below ; d, cervical series from the left side. All figures x |. 
lection the pubes are not preserved and the entire pelvis of Borhycena 
and A mphiproviverra is unknown. In Thylacynus the epipubic elements 
are mere vestigial cartilages (text fig. 3). 
