196 
DENNIS, ON CETACEAN BONES. 
the mastodon,, I am ignorant at present of its correspondence 
with the elephant in this respect. 
The very general similarity of cetacean bone is a great help 
in the matter, and nothing can be more striking than the com- 
parison of recent with fossil bone. Their agreement is shown 
in figs. 8, 9, 10, 11, Avith which the other figures of Crag and 
elephant bone, &c., bear no likeness. There seems, then, to 
me to be fair evidence, as shown by microscopical comparison, 
that the bones of Pachyderms, or at least of land animals 
perhaps of more massive proportions, are discoverable in the 
rolled Red Crag fossils. But perhaps a step even further may 
be gained. Fig. 12 represents the lacunae of the elephant ; 
fig. 5 a those of the hippopotamus ; and fig. 5 h those of the 
rhinoceros ; by which it may be seen that the free lacunse 
in each of these animals diff'er — those of the rhinoceros being 
more distinct and somewhat smaller than the elephant's, and 
those of the hippopotamus being larger ; and from noticing 
these distinctions, I have been led to suspect that in the 
rolled bones of the Crag several different genera are repre- 
sented. Fig. 13 very much compares with the bone of the 
hippopotamus by the intermixture of sets of larger lacunse, as 
also by the twisted characters of the Haversian bands; mi- 
fortunately the canaliculi are destroyed. Fig. 6, in its more 
perfect lacuna, agrees, perhaps, with the rhinoceros ; it has 
nothing whatever cetacean in its character. The Haversian 
tubes, in fig. 6, indicate a land animal, and one that moved 
with some speed over the ground, and such a disposition I 
have not yet found in any cetacean bone. Taking fig. 6, both 
as regards the Haversian tubes, lacunse, and canaliculi, it 
afibrds a most instructive instance of the existence of a land 
animal, of which we can obtain no further information than 
that which a small portion of its bone supplies us with ; that 
information, however, is important ; and we only wait for 
further knowledge concerning the disposition of the Haversian 
tubes to enable us, as it were, to replace the fragment in its 
proper position in the skeleton. At fig. 7 is a comparison of 
another Crag fossil with fossil elephant from the Himalayan 
mountains ; fig. 7 a represents the ordinary characters of 
very many of the Crag rolled bones ; fig. 7 h giving a portion 
of the vertebra of the fossil Himalayan elephant. Neither 
specimens of bones are very perfect in details, but are very 
similar in general characters, and appear to have experienced, 
before they became fossilized, a very similar partial decay. 
Fig. 14 a represents elephant bone from the Suffolk Gravel, 
much decomposed and hardly fossilized. This compares well 
with the recent elephant, and better with fig. 1 than with fig. 2 ; 
