THE OENiTHORYKCHUS PARADOXUS. 31 
as possessing much sensibility ; it seemed to me that the 
gustatory branch of the fifth was comparatively very small, 
but the hypoglossal nerves were large, and proportioned to 
the development of the strong muscles connected with, or 
entering into, the composition of the tongue. It is suffi- 
ciently curious, that the muscular apparatus supplying the 
tongue of the Ornithorynchus should much resemble that 
with which animals having a highly extensile tongue are 
furnished; yet, in the former, the lower surface of the 
tongue is so secured as to render extensive motions of this 
organ impossible. The tongue is fleshy and thick: at 
about j%ths of an inch from its base, or l^^^ths of an inch 
from its point, are inserted the lingual teeth, which, like 
the other teeth of the animal, are entirely cuticular, and 
tnay be removed by maceration along with the cuticle. I 
shall return to this subject when speaking of the organs 
subservient to digestion. The palate is marked by several 
transverse folds : deep notched indentations run along the 
sides of the lower bill, from its angle nearly to the point ; 
those of the upper bill are found only near the angle of the 
mouth. These reduplications of the membrane of the bill 
might be supposed to increase the sentient surface ; but it 
seemed to me that the nerves did not proceed to them in 
such abundance as to the anterior portions of the bill. I 
should consider, then, these folds as intended merely to al- 
low the mandibles to close very accurately, and thus to 
prevent the escape of those smaller insects on which pro- 
bably the animal feeds. 
Though the actual organ of hearing did not eome under 
my observation, still there presented themselves several 
appearances relative to those appendages, placed between 
it and the external air, which merit the attention of th6 
Society. There is no external ear, or rather there is no ear 
externally ; for although there be no cartilaginous projec- 
