21 
unconnected with a compound structure of the jaw; for there is 
not any suture in the compound jaw of a reptile which occupies a 
corresponding situation. 
The most numerous, the most characteristic, and the best marked 
sutures in the compound jaws of areptile, are those which define the 
limits of the coronoid, articular, angular, and surangular pieces, and 
which arechiefly conspicuous on the inner side of the posterior part of 
the jaw. Now the corresponding surface of the jaw of the Phascolo- 
there is entire; yet the smallest trace of sutures, or of any indication 
that the coronoid or articular processes were distinct pieces, cannot be 
detected; these processes are clearly and indisputably continuous, 
and confluent with the rest of the ramus of the jaw. So that 
where sutures ought to be visible, if the jaw of the Phascolothere 
were composite, there are none; and the hypothetical sutures that 
are apparent do not agree in position with any of the real sutures 
of an oviparous compound jaw. 
Lastly, with reference to the philosophy of pronouncing judg- 
ment on the saurian nature of the Stonesfield fossils from the 
appearance of sutures, Mr. Owen offered one remark, the justness 
of which, he said would be obvious alike to those who were, and 
to those who were not, conversant with comparative anatomy. ‘The 
accumulative evidence of the true nature of the Stonesfield fossils, 
afforded by the shape of the condyle, coronoid process, angle of the 
jaw, different kinds of teeth, shape of their crowns, double fangs, 
implantation in sockets,—the appearance, he repeated, presented 
by these important particulars cannot be due to accident; while 
those which favour the evidence of the compound structure of the 
jaw may arise from accidental circumstances. 
A paper was afterwards read, entitled “‘ Observations on the 
Structure and Relations of the presumed Marsupial Remains from 
the Stonesfield Oolite,” by William Ogilby, Esq., F.G.S. 
These observations are intended by the author to embody only 
the most prominent characters of the fossils, and those essential 
points of structure in which they are necessarily related to the class 
of mammifers or of reptiles respectively. For the sake of putting 
the several points clearly and impartially, he arranged his observa- 
tions under the two following heads :— 
1. The relations of agreement which subsist between the fossils 
in question and the corresponding bones of recent marsupials and 
insectivora. 
2. The characters in which the fossils differ from those families. 
Mr. Ogilby confined his remarks to marsupialia and insectivora, 
because it is to those families only of mammifers that the fossils 
have been considered by anatomists to belong; and to the interior 
surface of the jaw, as the exterior is not exhibited in any of the fossil 
specimens. 
1. In the general outline of the jaws, more especially in that of 
the Didelphys (Phascolotherium) Bucklandii, the author states, there 
is a very close resemblance to the jaw in recent imsectivora and 
insectivorous marsupials ; but he observes, that with respect to the 
