1006 MR. D. M. S. WATSON ON 
On the whole, there is nothing in the known structures of 
these two animals to prohibit a fairly close resemblance between 
them, but until Prof. Williston’s full description is published it 
is impossible to go beyond this. 
By far the most interesting comparison is between Broomia 
and a lizard. 
It is certain that the lizard palate must have been derived 
from one generally resembling that of Lroomia, and it is probable 
that it may have specially resembled that type in the possession 
of a very large interpterygoid vacuity and a very large para- 
sphenoid. 
The basisphenoid of Groomia at once recalls that of a lizard, 
but I know of none that really resembles it. 
The lower jaw of Lroomia is sutticiently generalised to have 
given rise to that of lizards, and very characteristic of that 
group is the short upstanding coronoid process. 
If the side of the temporal region of the skull be really cut 
away in Lroomia, we have a very striking resemblance to the 
Lizard type, where the narrowing of the primitiv ely single arch 
has produced the well-known present-day structure. 
The geckos have notochordal centra and intercentra, as has 
Lroomia. 
The articulation of the single-headed rib of Broomia is 
essentially similar to that of a lizard. The sacrum is also 
sunilar in the two groups of reptiles. 
The pectoral girdle of Broomia is extraordinarily similar to 
that which the primitive lizards must have possessed in the 
following features :— 
The reduction of the coracoidal elements to one on each side: 
this being, as Prof. Williston has pointed out, the anterior of the 
two of primitive reptiles. 
The long slender interclavicle with a rhomboidal head is a type 
from which the characteristic cross-shaped interclavicle of a lizard 
could be derived. A T-shaped interclavicle could not have 
produced this form. 
The somewhat expanded lower end of the clayicle is also a 
feature which was apparently present in the early lizards. 
There is nothing specially characteristic about the bones of the 
fore-leg in lizards, and they could be derived from those of 
Lroomia. 
The carpus of Lroomia differs as much from that of any lizard 
as it does from that of all other reptiles. 
The ium of Sroomia is completely lizard-like in its antero- 
ventral slope. The hind leg of Lroomia is not specially lizard- 
like. 
The only feature which we would expect to be present in an 
ancestral lizard which does not occur in Broomia is that modi- 
fication of the fifth digit, perhaps a divarication, which led to the 
modified fifth metatarsal found in Lizards, Sphenodon, Chelonia, 
Thecodonts, Crocodilia, ete. 
