no FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XIV. 



shows more polyprotodont than diprotodont characters. These are as 

 follows: 



1. Anterior root of zygoma only slightly in advance of end of 

 toothrow. 



2. Posterior root of zygoma not inflated. 



3. Tympanic narrow and annular. 



4. Petrous part of periotic largely exposed ventrally. 



5. Alisphenoid bulla not fused with paroccipital process. 



6. Foramina of squamosal arranged in general as in Dasyuridae. 

 Practically all of these characters relate to the otic bones or to the 



backward extension of the palate with relation to the zygomata. In the 

 extinct Pal&othentes, a close relative of C&nolestes, the zygomata and 

 palate are practically as in diprotodonts, so the polyprotodont char- 

 acters of the skull in casnolestids are reduced to those of the tympanic 

 region. The additional characters supposed to indicate polyprotodont 

 affinity and cited by Miss Dederer (1909) and Broom (1911) are found 

 in the smaller diprotodonts, as Dromicia and Tarsipes. Hence their 

 importance is doubtful. 



A few characters are at least in agreement with those of some 

 diprotodonts, and with no polyprotodonts so far as known. These are 

 the following: 



1. Upper anterior ethmo-turbinal short and enclosing but little of 

 the maxillo-turbinal. 



2. Maxillo-turbinal arising relatively high up on the nasal wall. 



3. Glenoid fossa relatively long and with a small postglenoid 

 process which is not extended transversely. 



4. A small foramen in masseteric fossa of mandible. 

 Distinctions in cranial characters between Ccenolestes and the 



didelphids are numerous; in fact the only characters in common are of 

 quite a general nature. 1 On the other hand, resemblances to Australian 

 forms, especially peramelids, are abundant. In the following respects 

 there is agreement with some or all Peramelidae or Dasyuridae and 

 disagreement with all Didelphyidae: 



1. Rostrum slender and elongate. 



2. Palatine processes of premaxillae not extending full length of 

 incisive foramina. 



3. Basioccipital concave medially. 



4. Maxillo-premaxillary suture nearly upright anteriorly. 



5. Cribriform plate approaching the vertical. 



6. Fronto-maxillary suture broad. 



1 The mastoid foramen may be an exclusive resemblance, but in the absence of 

 immature specimens I am unable to learn whether or not it occurs in dasyurids. 



