MAY, 1921. AMERICAN MARSUPIAL, C^NOLESTES OSGOOD. 139 



A comparison of C&nolestes with Spencer's figures and description of 

 Wynyardia, although rather unsatisfactory as a basis for positive con- 

 clusions, reveals a number of points in common. These may be enu- 

 merated as follows: (i) Cranial part of skull large as compared to facial. 

 (2) Relations of glenoid fossa to auditory meatus similar. (3) Squamosal 

 not inflated and posterior base of zygoma somewhat Dasyurine. 

 (4) Glenoid fossa relatively high. (5) Nasals extended anteriorly and 

 expanded posteriorly. (6) Premaxillae large and separated from the 

 maxillae by a suture which is only slightly oblique. (7) Mandibular 

 condyle relatively high. (8) Femoral trochanters similar and a third 

 tuberosity present as in Phascolomys. 



Comparison of Wynyardia with extinct American forms allied to 

 C&nolestes, as Palceoihentes and Abderites, also shows several interesting 

 points. Thus Palceoihentes has lambdoid and sagittal crests combined 

 with zygomata of a type similar to those of Wynyardia and the frontals 

 are widest in their cranial part. In Abderites, as previously noted by 

 Spencer, the seat of the large lower sectorial tooth forms a deep trans- 

 verse furrow in the mandible which seems closely comparable to the 

 condition in Wynyardia. 



Present material is not adequate for the positive conclusion that 

 Wynyardia is intimately allied to the American forms but the above 

 similarities are most suggestive and must be regarded at least in some 

 degree as strengthening belief in extensive community of relationship 

 between Australian and American marsupials, both polyprotodont and 

 diprotodont. 



RELATIONSHIPS OF MYRMECOBOIDES. 



The genus Myrmecoboides was established by Gidley in 1915 for an 

 incomplete lower jaw from the Paleocene (Fort Union) of Montana. 

 It was tentatively classified as belonging to the family Myrmecobiidae 

 and characterized as follows: "Canine semipremolariform, being 

 irregularly triangular in cross section and but slightly curved; canine 

 and the three simple premolars evenly spaced with short intervening 

 diastemae. There is also a short diastema between the canine and i 3 

 (the position of the other incisors is not known) . Fourth tooth behind 

 the canine (probably dp 4 retained) completely molariform; true molars 

 tritubercular, with well-developed basin heel, but with inner cusps of 

 trigonid (paraconid and metaconid) as high or higher than main outer 

 cusp (protoconid)." 



The principal characters regarded by Gidley as suggesting possible 

 affinity with Myrmecobius are (i) the diastemata between the premolars, 



