384 
PATAGONIAN EXPEDITIONS ! PALAEONTOLOGY. 
fourth is the longest. The shafts are more slender than that of the pollex 
and are slightly arched and more or less compressed in the dorso-palmar 
plane. 
The structure of the pelvis (Pis. LVII, figs 1, la ; LVIII, figs. 1, 7, 7 a) 
is important from the bearing it has on the thylacyne affinities of Clado- 
sictis. The anterior margin of the pubic symphysis is slightly damaged 
in the otherwise nearly complete pelvis of C. lustratus (No. 15,170). The 
anterior pubic border is sharp, without trace of supporting structures for 
epipubic bones. The pubic symphysis is closed, as in Thylacynus , so it 
seems probable that, if epipubic elements were present, they must have 
been vestigial cartilages, as in the latter genus ( cf. text-fig. 3). The pe- 
duncular portion of the ilium is more attenuated than in Prothylacynus , 
supporting heavy recti tubercles. The gluteal surface is broad and smooth 
with even less trace of muscular flutings than in Prothylacynus . The 
iliopectineal eminences are large. The ischial tuberosities are less pro- 
nounced than in Thylacynus . The obturator foramina are large and oval 
in outline, with the posterior border emarginated by an anteriorly directed 
prominence. 
The same lack of proportion between the lengths of skull and femur, 
which was mentioned in the discussion of the genus Borhycena , is observ- 
able to even a greater extent in the case of Cladosictis. The femoral shaft 
has a gentle sigmoid curvature, expanding at either end to about the same 
extent and in much the same manner as in Borhycena. The greater tro- 
chanter and head reach the same elevation. The lesser trochanter is 
prominent. As in Borhycena , the inner condyle is somewhat wider than 
the outer one. The intercondylar notch is deep and narrow, leading an- 
teriorly into a wide, shallow rotular groove, the margins of which are more 
acute than in Thylacynus (cf text-fig. 1, c). 
An ossified patella has not been found in association with any of the 
skeletal material of Cladosictis in the collection, and has accordingly been 
omitted in the restoration. 
The tibia (PI. LVIII, figs. 2, 8) resembles that of Prothylacynus , differ- 
ing, however, in being slightly narrower distally and in having the distal 
fibular facet less obliquely placed. The shaft is straight, in contrast with 
the curvature of the tibial shaft in Thylacynus (text-fig. 1, d). The cnemial 
crest is poorly differentiated, as in Prothylacynus , extending more than 
half way down the shaft. Distally, the tibia exhibits a trochlear surface 
