EASTMAN : CARBONIFEROUS SHARKS. 59 



Plates 2 and 3 was obtained a number of years ago by Mr. G. C. Merrill 

 from the Upper Coal Measures of Osage County, Kansas, and is preserved 

 in the Museum of Comparative Zoology at Cambridge (Cat. No. 749). The 

 second example, shown in Plate 1, was derived from the Upper Coal Meas- 

 ures of Cedar Creek, Nebraska, and belongs to the Museum of the Nebraska 

 State University at Lincoln. To Professor Edwin H. Barbour, Director 

 of the University Geological Survey of Nebraska, the writer is greatly 

 indebted for the privilege of studying and describing this and numerous 

 other Cai'boniferous fish remains which have been collected during the 

 prosecution of the Survey. Acknowledgments are also due to Miss 

 Carrie A. Barbour, of Lincoln, through whose skill and zeal these speci- 

 mens have been beautifully prepared or otherwise rendered available for 

 study. 



It is stated by Professor Barbour that when his specimen of the syra- 

 physial dentition of Campodus was discovered, it was in almost perfect 

 condition, and the slight injury it sustained on being extricated from the 

 matrix was subsequently repaired by his sister. For instance, a number 

 of the coronal buttresses on one side, and several of the coronal apices 

 were broken off; such of these as could not be mended from the original 

 fragments are now restored in plaster. As seen in Plate 1, the two 

 posterior coronal apices, and also the fourth and fifth counting from the 

 proximal end, are partly restored ; the remainder are in their original 

 condition. Weathering has removed most of the enamel from this 

 specimen, and indications of wear during life are not readily discernible. 



The Nebraska specimen is important from the fact that it first led to 

 an adequate understanding of the earlier known Kansas example, which 

 in turn disclosed a wealth of information respecting ancient types of 

 Cestraciont dentition, and furnished the solution of a number of debated 

 problems. For in the state in which the Kansas dentition originally 

 came to the Harvard Museum, all of the coronal apices having been 

 broken away, the complete form of the symphysial teeth was not re- 

 vealed, and their relations to Edestus were imsuspected. That this 

 specimen long ago challenged the attention of paloeichthyologists, 

 although no record of their views concerning it has come to light, is 

 witnessed by the fact that plaster casts were taken from it at the direc- 

 tion of Mr. Orestes St. John, while he was Assistant in Palaeontology at 

 the Museum under Professor Agassiz. Some of these replica, together 

 with casts of the lateral series described by St John and Worthen in 

 1875, have since found their way into other collections. 



From this statement regarding the history and condition of these 



