AND CLASSIFICATION OF THE FOSSIL REPTILIA. 
279 
classed by Sir R. Owen as Theriodonts. Kutorga, with only fragments of the 
humerus, recognized Mammalian characters, and regarded the aniaial to which they 
belonged as a Mammal. For this type, which Fischer named Eurosaurus in 1841, 
Kutorga adopted the name Brithopus; and I concur with Gaudry in preferring the 
older name. Eichwald’s conception was, however, a remarkable one. He states 
(‘Letbeea Rossica,’ p. 1630) that Eurosaurus has the skull of a Labyrinthodont, with 
vertebrae and phalanges like those of Mastodonsaurus, and the femur, tibia, coracoid, 
and scapula like Pelorosaurus and Hylceosaurus ; and he associated Kutorga’s genera 
Brithop)iis and Orthopus as the humerus of that animal. The foundation for this 
interpretation is partly in the skull which von Meyer named Melosaurus, and 
regarded as Labyrinthodont; and, reviewing Eichwald’s work, that writer considered 
the association of bones so dissimilar in size and character in one animal to be improb¬ 
able. It is impossible to form an independent opinion without studying the original 
materials at Moscow and St. Petersburgh; but the Labyrinthodont character of the 
skull of Pareiasaurus, and many other Labyrinthodont features in the vertebral 
column, in combination with Dicynodont characters in the pelvis, may justify a 
suspension of judgment on the conclusions adopted by Eichwald. But whether the 
Orenburg fossils should prove to be allied to Pareiasaurus, or to some other Anom- 
odont type, they are associated with remains named Rhopalodon, which voN Meyer 
compares in its teeth to Galesaurus, though the palate carries a row of small conical 
teeth on the hinder outer margin of the pterygoid; and the same beds yield Deutero- 
saurus, which voN Meyer compared with the Bathygnathus of Leidy. 
In this type there are eleven dorsal vertebree at least, and, according to Eichwald 
and Owen, two sacral vertebrm, though yon Meyer inclines to think there may 
have been three, and that the strong transverse process of the eleventh dorsal 
contributed to support the ilium, although that vertebra was not united with the 
sacrum. Every dorsal rib unites with two transverse processes, in this respect 
probably rather approximating to the type of Pareiasaurus than to Dicynodonts. 
There can be no doubt that the pelvis was also substantially formed on the Dicyno¬ 
dont plan, though the- antero-posterior processes of the ilium appear to have been 
much less developed even than in Phocosaurus. In 1866, voN Meyer described some 
additional remains from Orenburg, which he referred to Eurosaurus verus, and which 
may be accepted as making better known the skeleton of Brithopus priscus of 
Kutorga. I have examined the figured bones preserved in the Senckenberg Museum. 
They comprise a fragment of a large tooth with a finely serrated border, comparable 
to canine teeth in many South African genera, described by Sir R. Owen as Theri- 
odont. Von Meyer remarks on the close resemblance of the posterior part of the skull 
to the corresponding region of Dicynodon. It is obviously formed on the same 
general plan, but the foramen magnum is triangular, and broader than high. The 
occipital condyle, which is also very wide, appears to be tripartite, as in Dicynodonts. 
There is a median excavation below the basi-occipital part of the condyle, though this 
