98 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 



EXPLANATION OF PLATES. 



PLATE 1. 



Campodus variabilis (Newb. and W.) Coal Measures; Cedar Creek, Nebraska. 

 Symphysial dentition, belonging presumably to the lower jaw, and displaying 

 eleven fused teeth, viewed from the riglit-hand side. Reproduced from a photo- 

 graph by Mr. A. Hyatt Verrill without retouching. Original preserved in the 

 Museum of the State University of Nebraska. X |. 



PLATE 2. 



Campodus varmbilis (Newb. and W.). Coal Measures; Osage County, Kansas. 

 S3'mpiiysial dentition belonging presumably to the lower jaw, with naturally 

 associated antero-lateral series, viewed from the right-hand side. Coronal apices 

 of all except the posterior tootii have been broken away. Reproduced from a 

 photograpii by Mr. C. H. Currier without retouching. Original preserved in the 

 Museum of Comparative Zoology at Cambridge, Mass. (Cat. No. 749). X |- 



PLATE 3. 



Fig. 1. Campodus variabilis (Newb. and W.). Coal Measures; Osage County, 

 Kansas. Oral aspect of same specimen shown in Plate 2, with the 

 anterior extremity shown uppermost. X g- 



Fig. 2. Ctenacanthus venustus, sp. nov. Kinderliook limestone ; Iowa (?). Lateral 

 aspect of spine referred to the anterior dorsal fin, and belonging to an 

 immature individual. Original preserved in the United States National 

 Museum at Washington. (Cat. No. 3385). X i- 



PLATE 4. 



Campyloprion annectans Eastm. Carboniferous or Permo-Carboniferous ; locality 

 ttnknown. Symphysial dentition, showing portions of about 20 fused teeth, 

 viewed from the left-hand side. Reproduced from a photograph by Mr. C. H. 

 Currier witliout retouching. Original preserved in the Museum of Comparative 

 Zoology at Cambridge, Mass. X |- 



