THE DEVONIAN FISHES OF MISSOURI 73 



Plate III 



Fig. 1. Dinichthys rowleyi sp. nov. Incomplete left vomerine 



tooth, about 2-3 natural size. Page 60. 

 Figs. 2 and 6. Fin rays of a dinichthyid, about 2-3 natural 



size. Page 63. 



Figs. 3 and 4. Tritors of Ptyctodus calceolus Newb. and Worth- 

 en, about 2-3 natural size. Page 64-65. 

 Fig. 5. Under side of an external occipital of Dinichthys 



about 2-3 natural size. Page 63. 

 Fig. 7. Unidentified bone of an arthrodire, about 2-3 natural 



size. Page 63. 

 Fig. 8. Dental plate of Conchodus variablis Eastman, about 



2-3 natural size. Page 65-66. 



All of the specimens figured on this plate are from the top 

 of the Devonian at Louisiana, Mo. 



Plate IV 



Figs. 1, 2, 5, 6. Helodus clivulus sp. nov. Figs. 1 and 2 top and 

 side views of an almost complete tooth. Figs. 5 and 6 top 

 and side views of a smaller incomplete tooth. From the 

 top of the Devonian at Louisiana, Mo. Page 67. 



Figs. 3 and 4. Ptyctodus ferox Eastman. Side and top views 

 of a specimen from the Craghead Creek shales of Callaway 

 County, Mo. Page 63-64. 



Figs. 7-10 and 17. Specimens of Helodus from the Chouteau 

 limestone of Sedalia, Missouri. Fig. 7 shows the union 

 of two teeth to form one. Page 66. 



Figs. 11-16. Helodus incipiens sp. nov. Top and side views of 

 the four co types. Fig. 12 is a side view of the specimen 

 shown in fig. 11, and fig. 15 is a side view of 13. Top 

 of the Devonian at Louisiana, Mo. Page 67. 



Fig. 18, Psephodus sp. undet. Top view of a specimen from 

 the top of the Devonian at Louisiana, Mo. Page 68. 



Figs. 19 and 20. Helodus devonicus sp. nov. Side and top views 

 of the type. Top of the Devonian. Louisiana, Mo. Page 

 66-67. 



