On MESOSAURUS BRASILIENSIS nov. sp. 
FROM THE 
Permian of Brasil 
The fossil reptilian remains which form the basis of the fol- 
lowing report occur in bituminous shales from the Permian of South- 
ern Brasil. 
Most of the specimens were collected near Iraly station, 
S. Paulo e Rio Grande R. R., slate of Paranda, while a few are from 
a locality near André Reboucas station. The material is the property 
of the Brazilian Coal Commission, and was sent to the American 
Museum of Natural History, New York, by Dr. I. C. White, Chiefof the 
Brasilian Coal Commission. I have studied the material and have 
prepared the following report : 
The matrix containing most of the remains isa black bitumi- 
nous shale, which splits rather readily in the plane of the specimen 
thus exposing, in some cases, almost the entire skeleton. A few 
bones were found in a slate-colored clay relatively free from bitumi- 
nous matter, and the collection also contains one or two fragments 
of coarse marlin which were found a number of disarticulated bones 
which are brownish in color and very hard. The skeletons found 
in the bituminous shale are almost completely carbonized, and occa- 
sionally covered with a delicate pellicle of pyrite. They are much 
softer than the matrix, very friable indeed, and crumble badly on 
exposure to the air. Owing tothis crumbling, it was found that the 
only way to study the remains satisfactorily was carefully to remove 
the carbonized bones and to lake casts of the molds. From these 
natural molds or negatives, gelatine positives were first made, then, 
from these gelatine negatives, and from the gelatine molds final 
positive casts were made in plaster of Paris. Aided by careful com- 
parison with the originals and with the gelatine positives, the plaster 
casts were colored to differentiate bone from matrix, and thus they 
illustrate the skeletal structures more clearly than do the originals. 
The casts were photographed by Mr. A. E. Anderson, and some 0 
