198 
DENNIS, ON CETACEAN BONES. 
fossils, sucli as are shown in tlie plate, having established 
in my mind the leading distinctions that appear to exist be- 
tween the elephant and the whale as respects the micro- 
scopical characters of their bone, though I cannot positively 
identify the Crag fossils with either the recent or fossil 
elephant, yet their much greater analogy with the elephant 
than with the whale, their agreement in all essential par- 
ticulars with the pachydermal type, — (as indicated by the 
greater fineness and number of the canaliculi, hj the greater 
uniformity of the lacunae, and also, with great probability, by 
the characters of the Haversian tubes) — induce me to con- 
clude that the animals to which such bones once belonged 
were not truly aquatic in their habits, but were land animals, 
or, if at all aquatic, that they had the means of terrestrial 
progression such as are enjoyed by large Pachyderms. The 
considerable thickness of the cortical portion of the bone in 
these Crag fossils appears also to afford another argument 
against their cetacean origin, for the apparently massive jaws 
of the whale have only a thin coating of cortical substance 
enclosing the cancellous structure. I do not know why we 
should disbelieve the evidence I have adduced of the existence 
of these Pachyderms, when portions of the teeth of the mas- 
todon have been obtained from the Red Crag, of which there 
is a rolled fragment in the Museum of Bury St. Edmunds. If 
the rolled bones which I have examined are cetacean, they are 
microscopically distinct from all known Cetaceans which I 
have had the means of examining ; but supposing I am mis- 
taken, still the subject is of sufficient interest to justify an 
inquiry, nor am I aware that the attempt has been made 
before, either to draw a comparison between the microsco- 
pical characters of the bone of Cetaceans and Pachyderms, 
or to figure any of the rolled bones of the Suffolk Crag. 
But the question arises, where and when did these 
animals live ? Fresh disclosures are now daily coming to 
light in reference to the ancient mammalia of the earth. To 
say nothing of the Microlestes of the Trias of Wirtemberg, 
or of the rib-bone from the Lyme Regis bone-bed, and which 
the inimitable engraving of Mr. Tuffen West, as given in 
the 16th number of this journal, shows could have belonged 
to no other animal than a mammifer, nor to mention the 
four Stonesfield mammalian jaws,"^ one of which, the Stereo- 
gnathus ooliticus, I discovered myself, we have now the 
announcement from Sir Charles Lyell, in his Supplement to 
* That is, of four distinct animals, viz., AmfMtherium Frevostii, A. 
Broderi])iii Fharcolotherium Buoklmdi, and my Stereognathus Ooliticus. 
