sternum resembles that of the ornithorhynchus paradoxus. 29 
rhynchus paradoxus, from the form of its vertebras, swims 
like the whale tribe, and breathes air, but does not, like them, 
reside constantly in the water, as no animals covered with 
hair do. 
As neither fishes, nor animals of the whale tribe, have 
any thing in the form of the sternum, or of the muscles that 
are attached to it, that is similar to what is met with in the 
fossil animal and ornithorhynchus, these last animals, in that 
respect, make an approach to the bird, in which the sternum 
has still greater breadth, and the muscles greater strength. 
In finding that this structure of sternum is wanting in the 
whale tribe, it leads to an enquiry into the peculiarities of 
the habits of life of the ornithorhynchus, and the animal to 
which the fossil bones belonged, that make such a structure 
necessary. 
The ornithorhynchus has its fauces and stomach commonly 
filled with sand and gravel, which renders it probable that it 
feeds at the bottom of the lakes and rivers in which it is met 
with ; and as it must come to the surface to breathe at short in- 
tervals, this apparatus will enable it to rise with an unusual 
degree of velocity; and would answer the same purpose 
in the animal whose sternum has a similar construction. 
Nothing of this kind is required in the whale tribe ; they are 
rendered sufficiently buoyant by the oil they contain. 
There is a fossil bone found in the same place, having so 
nearly the same colour and general structure as those of 
this animal, that it seems to belong to it. In its form it bears 
a resemblance to the first bone of the pectoral fin, only much 
larger in all respects, it therefore may be conjectured to be 
