190 
PROFESSOR H. G. SEELEY OR THE STRUCTURE, ORGANIZATION", 
evidence that any were contained in sockets. And, if so, the evidence disappears 
which would refer the animal to the Thecodontia. The other characteristics mentioned 
are essentially a summary of the views of Cuvier and von Meyer, unsupported by 
new evidence. 
Professor Huxley discussed this animal in his ‘ Anatomy of Vertebrated Animals,’ * 
classing it with Lizards, in a position intermediate between the fossil group 
Homceosauria and the Platynota, which comprises the Old World Monitors. Von 
Meyer’s suggestion that it is the type of a new group is adopted, and the group is 
named Protorosauria. The skull is said to be of moderate size, preserved in one 
specimen only ; and in that it is in such an imperfect condition that the details of its 
structure cannot be made out. The teeth, however, are nearly straight, conical, and 
sharply pointed, and seem to have been implanted in distinct sockets, though there 
may be some doubt on this point. The tail is long and slender, and the limbs well 
developed, as in the existing Monitors. In the abdominal region numerous short and 
filiform bones appear to represent and correspond with the abdominal ribs of 
Plesiosauria and Crocodilia. Beyond the middle of the tail the spinous processes 
bifurcate, so that each vertebra seems to have two spinous processes, a peculiarity 
unknown in other Lacertilia. The large chevron bones are articulated between the 
bodies of the caudal vertebrae, as in Crocodilia, but also as in some Lacertilia, such as 
the Geckos. In the pes the number of phalanges is characteristically Lacertilian, and 
so is the form of the metatarsals. The tarsal structure is compared with that of the 
Geckos. I find the skull crushed and badly preserved, but perfectly intelligible. 
A specimen from Durham, described by Messrs. Hancock and Howse, adds nothing 
to the scientific history of the type, beyond its presence in a British Permian deposit. 
In these several studies there are substantially only two interpretations of 
Protorosaurus; first, Cuvier and Huxley class it unreserved^ with Lizards ; 
secondly, von Meyer and Owen refer it to a new Beptilian type. Von Meyer 
affirmed that it is neither Lizard nor Crocodile; but saw in it resemblances to those 
animals, as well as to Archcegosaurus and Pterodactyles. The difficulty in harmonising 
these different views has been partly in want of knowledge of the skull. 
Professor Charles Stewart, Conservator of the College of Surgeons Museum, 
having recently rearranged the Reptilia, and placed Spener’s fossil in an accessible 
position, I have been able to make some notice of its structure. And I have to thank 
the President and Council of the College for permission to obtain drawings of the 
remains ; and to thank Professor Stewart and Dr. Garson for facilities afforded me 
in making the following description of the type of Protorosaurus Speneri. 
* V. 226, 1871. 
