BY J. T. WILSON. 147 



pretation to the " os paradoxum " in OrnithorhyncJms, and the 

 definition of it as a true premaxillary element certainly holds the 

 field. At the same time, when the significance of the statements 

 of Parker and Howes for the interpretation of the premaxilla of 

 other mammals is borne in mind, it may be necessary to admit 

 that the distinction of the dumb-bell bone as vomerine rather 

 than premaxillary is largely a nominal one. I submit, nevertheless, 

 that this nominal distinction is an important one, and I am 

 inclined to hold that a full recognition that here in Ornithorhynchus 

 the bone lying between the incisive or naso-palatine foramen and 

 the mesial palatal suture is ti-uly vomerine and has in its origin 

 nothing to do with the body of the premaxilla, will help us to 

 clearer views upon the constitution of the corresponding region 

 in mammals generally. 



[See Appendix, p. 150.] 



REFERENCES TO LITERATURE. 



(1) Wilson and Martin. Macleay Memorial Volume (Linn. 



Soc. N.S.W. 1893). 



(2) Meckel, J. F. " Ornithorhynchi paradoxi descriptio ana- 



tomica" (Lipsiae, 1826). 



(3) Owen, R. " Monotremata," Todd's Cyclopaedia of Anatomy 



and Physiology. 



(4) Owen, R. "Anatomy of Vertebrates," Vol. ii. 



(5) Flower, W. H. " Osteology of the Mammalia " (London, 



1876). 



(6) Flower and Gadow. Id., 3rd edition (London, 1885). 



(7) Albrecht, p. " Sur la Fente maxillaire double sous- 



muqueuse et les 4 os intermaxillaires de I'Ornithorhynque 

 adulte normale" (Bruxelles, 1883). 



(8) Turneu, W. "The dumb-bell shaped Bone in the Palate of 



Ornithorhynchus compared with the prenasal Bone of the 

 Pig," Journal of Anat. and Physiol, xix. p. 214. 



