TONGUE OF ORNITHOIiUYNOHUS PARADOXUS. 467 



SO effective, nor is there the same necessity for such protection. 

 Beneath the sphincter are cells with a meridional arrangement 

 Avhich must act as a dilator muscle (fig. 8). 



The posterior gustatory areas {p h o, figs. 1 and £) are very 

 similar, but there is less need for protection in a deep furrow, 

 because of the posterior position and situation in a slight groove 

 overhung by a fold. Hence the gustatory ridges rise to the 

 surface (figs. 10 and 11), and bear some resemblance to an 

 ordinary circumvallate papilla, but the bulbs are placed on the 

 upper surface and sides, as in the anterior organ, and unlike 

 any gustatory area yet described in Mammalia (except the iso- 

 lated bulbs on the fungiform papillse). This description only 

 applies exactly to the right posterior area, for there was a great 

 lack of symmetry in this specimen. The left area appeared to 

 be rudimentary, and was only represented by a slight ridge at the 

 bottom and rather on the anterior side of a furrow, with few 

 bulbs, and these often placed beneath the epithelium or only 

 partially embedded in it. Some, however, were situated nor- 

 mally, and possessed pores. I am unable to state certainly that 

 this lack of symmetry is abnormal, but it is very probable that 

 this is the case, considering that the anterior areas entirely re- 

 semble each other. The structures accompanying the gusta- 

 tory ridges, in all cases (even the rudimentary left posterior 

 ridge), are the same as those of other Mammalia. The serous 

 gland-ducts open as usual into the spaces round the ridges, and 

 this type of gland is not found elsewhere in the tongue. The 

 structure of the gland-cells did not seem to be identical with that 

 of the usual serous type, but this is probably due to post-mortem 

 changes, especially as the mucous glands have also undergone 

 alteration. The ducts of the serous glands sometimes contain 

 nuclei and the debris of cells. Non-medullated nerve-fibres 

 almost fill up the centre of the ridge and radiate outwards to 

 end in the bulbs. I was surprised to find no indications of 

 ganglion-cells (as described in Perameles), although minute 

 ganglia occur on the large nerve-branches. Beneath the pos- 

 terior gustatory areas a tissue resembling adenoid tissue occurs 

 in rather large amount (fig. 10), and traces of it can be found 



