THE SUPPOSED NASAL VALVES OF ORNITHORHYNCHUS, 317 
Note on the Supposed Nasal Valves of 
Ornithorhynchus. 
By Rozgrt Broom, M.B,,C.M., B.Sc., Taralga, New South Wales, 
[Read 28th May, 1895.] 
In a recent paper by Professor Symington,* he gives a short account 
of the peculiar structure of the anterior part of the nose of 
Ornithorhynchus, and describes the condition as seen in a series of 
vertical transverse sections, While in the main I can confirm the. 
correctness of his observations, my examination enables me to 
come nearer a definite conclusion as to the function of the septa 
or valves found in the anterior part of the nasal cavities, 
Professor Symington describes and gives figures of the three 
compartments of the nasal passage seen on section, but in his 
sections he finds the middle compartment always the larger, and 
regards the partitions as the walls of two ceecal pouches placed one 
above, the other below the air-passage. He opposes the view of 
Meckel t (the only other anatomist who appears to mention them) 
that the flaps form a nasal valve, and states that in his sections 
“they do not appear sufficiently large and free to meet one another 
so as to close the anterior part of the nose,” and adds that “it ig 
obvious that, were they to do so, they would constitute a serious 
obstacle to inspiration of air through the nose.” 
In making sections of the beak of Ornithorhynchus recently to 
study Jacobson’s Organ, my preparations, I found, threw unex- 
pected light on the valves. The Platypus had been shot in the 
head, and one small lead pellet had injured the outer wall of the 
nasal passage on one side, driving a little piece of cartilage into the 
middle of the passage, Here, on section, it was found firmly held 
by the two flaps of the valve. Not only had the flaps come 
together, but the contraction was further indicated by the walls 
* Proc. Zool. Soc., 1891, p. 575. 
t Ornithorhynchi paradoxi descrip, anatomica, Lipsie, 1826, 
