202 HISTORICAL PALZONTOLOGY. 
Thuringia, but other allied species have been detected in the 
Middle Permian of Germany and the north of England. This 
Reptile attained a length of from three to four feet ; and it has 
been generally referred to the group of the Lizards (Lacerti/ia), 
to which it is most nearly allied in its general structure, at the 
same time that it differs from all existing members of this group 
in the fact that its numerous conical and pointed teeth were 
implanted in distinct sockets in the jaws—this being a Croco- 
dilian character. In other respects, however, Protorosaurus 
approximates closely to the hving Monitors ( Varanide) ; and 
the fact that the bodies of the vertebrz are slightly cupped or 
hollowed out at the ends would lead to the belief that the 
animal was aquatic in its habits. At the same time, the 
structure of the hind-limbs and their bony supports proves 
clearly that it must have also possessed the power of progres- 
sion upon the land. Various other Reptilian bones have been 
described from the Permian formation, of which some are pro- 
bably really referable to Labyrinthodonts, whilst others are 
regarded by Professor Owen as referable to the order of the 
“Theriodonts,” in which the teeth are implanted in sockets, 
and resemble those of carnivorous quadrupeds in consisting 
of three groups in each jaw (namely, incisors, canines, and 
molars). Lastly, in red sandstones of Permian age in Dum- 
friesshire have been discovered the tracks of what would ap- 
pear to have been Chelonians (Tortoises and Turtles); but it 
would not be safe to accept this conclusion as certain upon the 
evidence of footprints alone. The Chelichnus Duncan, how- 
ever, described by Sir William Jardine in his magnificent work 
on the ‘Ichnology of Annandale, bears a great resemblance 
to the track of a Turtle. 
No remains of Birds or Quadrupeds have hitherto been 
detected in deposits of Permian age. 
LITERATURE. 
The following works may be consulted by the student with regard to the 
Permian formation and its fossils :— 
(1) ‘*On the Geological Relations and Internal Structure of the Magne- 
sian Limestone and the Lower Portions of the New Red Sand- 
stone Series, &c.”—‘ Trans. Geol. Soc.,’ ser. 2, vol. iii. Sedg- 
wick. 
(2) ‘The Geology of Russia in Europe.’ Murchison, De Verneuil, and 
Von Keyserling. 
(3) ‘Siluria.’ Murchison. 
(4) ‘ Permische System in Sachsen.’ Geinitz and Gutbier. 
) ‘Die Versteinerungen des Deutschen Zechsteingebirges.’ Geinitz. 
(6) ‘Die Animalischen Ueberreste der Dyas.’ Geinitz. 
