2 , 8 ] 
RECORDS OF W.A. MUSEUM. 
possible that more bones may yet be recognised as belonging to- 
this animal, but this is not probable, as the bones were carefully 
sorted out upon several occasions. 
Taking into consideration all the bones examined and referred 
to above, there seems a close relationship between this specimen 
and the platyrhine form as exemplified by Owen’s P. platyrhinu%\. 
on the other hand, there are striking points of difference. For 
instance, of the skull, those, most important bones, the nasals, 
though longer and having a greater “ least breadth ” than the 
corresponding bones of P. platyrJiinus, are very slender when their 
greatest breadth is concerned, thus suggesting in a general way the 
narrower form of the cranium proper which is so marked in the 
post-orbital region. 
The greater lateral extent of the zygomal arches, bringing up 
to normal the greatest breadth of the skull, is also a point that 
must not be overlooked. 
In the mandible we have several variations, chief amongst 
them being the contour of the under surface. 
The scapula, humerus, radius and femur all appear to vary 
from the corresponding bones of the continental species, so that 
there seems some justification for considering the Mammoth Cave 
form a species distinct from all of them. 
Specific Characters. 
Skull. Large, of the platyrhine type, with a basal length of 
179mm. ; nasals large, expanded behind, but less so than in 
P. mitchelli, their greatest breadth five-eighths of their length, their 
lateral margins undulate, posterior border convex ; width of cranial 
portion of skull, exclusive of the zygomae, much less in proportion! 
to the basal length than in the other forms ; zygomal arch very 
large ; extent of the naso-premaxillary suture twice as long as the 
naso-maxillary suture. 
Teeth. Upper incisors comparatively broad, oval in section,, 
faintly grooved ; lower incisors sub-triangular in section, their 
breadth less than their depth ; molars as usual. 
Size of the animal. As large as P, mitchelli. 
I have named this Wombat Phascolomys hacketti, in honour of 
the distinguished Doctor, who is Chairman not only of the Museum 
