BY n. BROOM. 209 



I have given no name; but, on the whole, my paper would have 

 remained much as it is. Whether morphologists accept all 

 Gaupp's conclusions or not, all must be most grateful for a most 

 beautiful piece of conscientious work. 



When one compares the skull of the very young Echidna with 

 that of the young Dasyurus, one is at once struck by the remark- 

 able similarity between the two. In fact the Dasyure skull 

 resembles that of Echidna more than it does that of Trichosurus. 



Echidna agrees with Dasynrus in having a broad, flat, nasal 

 floor-cartilage {solum nasi), and in having the paraseptal carti- 

 lages ending in a point. There is an absence in Dasyurus of the 

 palatine-process of the solum nasi, seen in Echidna. The nasal 

 capsule behind joins the median cartilage in much the same way 

 in both. 



The cartilage which I have called the alisphenoid, Gaupp calls 

 the ala temporalis. It is similarly situated in the Dasyure and 

 Echidna, but the marsupials reveal the meaning of the structure 

 much better than the monotreme. In Echidna there is a small 

 cartilaginous process passing upwards and forwards to join the 

 orbitosphenoid, but this is apparently not homologous with the 

 process in Dasyurus. The position of the carotid foramina 

 diSers somewhat, being much nearer the middle line in Echidna. 

 The marsupial condition is thus intermediate between the mono- 

 treme and the eutherian. 



The parachordal region in Echidna is a little narrower than in 

 Trichosurus, and much narrower than in Dasyurus. The occipital 

 cartilage differs in having, in the marsupials, two foramina for 

 nerve xii.; while, in Echidna, nerve xii. passes, according to 

 Gaupp, with x. and xi., through the jugular foramen. 



The auditory capsules resemble each other in the two groups 

 owing to the cochlea being simply curved and not coiled in either. 

 The section shown by Gaupp in Plate Ixxii., fig. 19, should be 

 compared with ray fig.31, and the near affinity of the monotreme 

 and the marsupial will be manifest. In all essential features 

 there is close agreement. 

 15 



