188 KANSAS UNIVERSITY SCIENCE BULLETIN. 



zu erkennen sind, viel weniger irgend welche Einzelheiten der 

 Organization. Hier konnte nur eine griindliche imd sorgfaltige 

 Preparation zum Ziele fiihren. Es wurde dabei durchwegs-im 

 Anschluss an die oft mit grossem Nutzen angewandte Methode 

 Jaekel's der Knochen entfernt, wobei verhaltnissmassig gute 

 Negative erhalten wurden. Eine grosse Erleichterung war 

 dadurch ermoglicht, dass sich die Knochensubstanz in Salz- 

 saure lost, wahrend die Kohle nicht angegriffen wird. Die 

 iibrigbleibenden Teilchen des Knochens wurden dann mit der 

 Nadel unter starker Vergrosserung entfernt. 



"Fur die Abdriicke wurde zum grossten Teile Guttapercha 

 dann aber auch Gips und in geringerem Masse auch Gelatine 

 und Wachs verwendet." (p. 64.) 



Much the same method has been employed by McGregor (3) 

 in his study of Meosawus brasiliensis , which was embedded in 

 a black bituminous shale from the Permian of Brazil. He says : 



"The matrix containing most of the remains is black bitu- 

 minous shale, which splits rather readily in the plane of the 

 specimen thus exposing, in some cases, almost the entire 

 skeleton. The skeletons found in the bituminous shale are 

 almost completely carbonized, and occasionally 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 to this crumbling, it was found that the only 

 way to study the remains satisfactorily was carefully to re- 

 move the carbonized bones and to take 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 comparison with the originals and 

 with the gelatine positives, the plaster casts were colored to 

 differentiate bone from matrix, and thus they illustrate the 

 skeletal structure more clearly than do the originals." 



The fossils studied by the writer were of such a nature 

 that neither of the above methods was possible. This was 

 due to the fact that most of the material was borrowed from 

 the American Museum of Natural History, and the specimens 

 representing the species are not sufficiently abundant to admit 

 of preparation. Furthermore, a great many of the specimens 

 studied were Cope's types, and as such, of course, could not be 

 disturbed. Under these circumstances new methods of study 

 had to be devised. 



The fossils from Linton, especially, are all embedded in a 

 soft coal, which is usually much broken, as if it had been 

 picked up from the mine dump. The skeletal elements in all 



