200 
PROFESSOR H. G. SEELEY OR THE STRUCTURE, ORGANIZATION, 
are the impressions of four digits, which successively augment in length. They show 
the increasing number of bones, indicated by the formula 2.3.4.5. All the articular 
surfaces of the phalanges are perfectly ossified, and they are shaped as in Dinosaurs, 
hut an approach to this perfect ossification is seen in the Homoeosaurs and other 
fossils. The terminal phalanges of the digits are in the form of claws, curved and 
pointed, and compressed from side to side. 
Armature of the shin. —In the region of the early dorsal vertebrae a fragment 
is exposed of a very thin plate of bone which was at least 3 centims. long. It is 
made up of a number of minute oblong bones, each 1 millim. wide, suturally united 
together into a shield across which a slight longitudinal keel runs. This plate I regard 
as a piece of dermal armour. (Plate 15, fig. 11.) 
Part III. 
Comparison between the Type in the Royal College of Surgeons Museum and other 
Specimens referred to Protorosaurus Speneri by yon Meyer. 
Before an attempt is made to explain the structure of this type of animal, it is 
necessary, on account of its imperfect preservation, to discuss its relations with the 
specimens figured by yon Meyer. That great anatomist was disposed to regard the 
differences between the fossils as due to asre and resultant differences in ossifi- 
cation, though he did not decide absolutely on the specific identity of the whole 
of the materials. Unless the specimens could be brought together, it would be 
difficult to determine their relations so as to assign its systematic place to each, for 
the animals have so much in common, and the differences between them are not at 
first obvious. Nevertheless, if the method of comparison is applied, I believe the 
I’esult will show that von Meyer’s species is really a family including several species, 
and more than one genus. 
The available data for comparison in the type specimen are remarkably scanty. It 
has been shown that the femur is 7*1 centims. long, and that it is seven times as long 
as the caudal vertebrae, which are almost uniformly 1 centim. long. The cervical 
vertebrae also yield some characters in the form of the neural arch and the ridges on 
the centrum. 
There is no other specimen with the femur so short, but the differences in the length 
of the bone are so slight that they might at first pass for gradations of growth, their 
lengths in centims. being 7*1, 8*3, 8'8, 9*7, 10. All the bones, however, do not vary 
in the same ratio. 
I will first contrast the type with the specimen described by Link, known as the 
Waldenburg specimen. In that specimen (von Meyer, l.c., T. 9) the caudal vertebrae 
augment in length from 1 '3 centim. in the early caudal to 1*8 centim. at the twenty- 
fourth caudal, where the specimen is fractured. The femur is 10 centims. long, but it 
