BY PROFESSOR J. T. WILSON. 59 



proved to be a perfectly distinct element — a true anterior vomer. 

 (5) Anteriorly, the ventral premaxillary splints turn up dorsally 

 in front of the anterior extremity of the snout in both Ornitho- 

 rhynchus specimens, in the form of rather attenuated trabecule, 

 lodged in the notch between the alar expansions of the rostral 

 cartilage. Above this plane they fuse and are continued dorsally 

 into a remarkable osseous mass which forms a definite skeletal 

 foundation for the caruncle, and may therefore be named the os 

 caruncuhe. This is at its maximum development in the younger 

 stage of Omiihorhynchus, and is undergoing resorption in the older; 

 whilst in the Echidna model it is only represented by a small 

 nodule of bone which has lost all connection with the premaxillse. 

 From Seydel's figures of earlier stages it is evident that the 

 Echidna condition is originally identical with that of Omitho- 

 rhynchus, though it would appear to exist in a less exaggerated 

 form. (6) The cartilaginous septum of both Monotremes ex- 

 hibits an oval " internasal fenestra " immediately behind its 

 anterior termination at the prerostral notch. A similar fenestra, 

 according to W. K. Parker, is " a common feature in low 

 Eutheria." 



CATALOGUE OF THE DESCRIBED MOSSES OF NEW 

 SOUTH WALES. 



By Rev Walter W. Watts and Thomas Whttlegge, PR M S. 



To be issued separately with one of the later Parts of this Volume. 



