ART. 12 CLASSIFICATION OF CONODONTS ULEICH AND BASSLER 63 



Fig. 18. Bryantodus (jermaniis, new species 25 



View of the type sliowing relationship to B. hisolens. 



19,20. Prioniodella informata, uew species 20 



Two teetli sliowing denticles increasing in length toward 

 middle. 



21. Prioniodella brevispina, new species 20 



Tooth showing characteristic thick bar and short length 

 of denticles. 



22,23. Prioniodella gracilis, new species 20 



Two teeth exhibiting the denticles directed obliquely 

 backward. 



24. Prioniodella. robusta, new species 20 



Tooth showing large erect denticles and absence of spur. 



25. Prioniodella conferta, new species 21 



View of tooth illustrating closely arranged, obliquely set 

 denticles. 



Plate 11 



1. Jaw, X 2.5, of small selachian from Sandwich Islands, showing teeth 



and dermal plates. 



2. Teeth of same, X G, illustrating median denticles and basal prong for 



attachment in jaw, similar to conodonts. 



3. Dermal plates of the same specimen, X 20. 



4, 5. Portion of jaw of a recent shark, X 2.5 and X 6, exhibiting arrangement 

 of teeth and their similarity to conodont genera like Bryantodus. The 

 little variation in the shape of the teeth is also apparent. 



6. Outer and inner sides of jaw of a recent myxiue fish {Myxine glutinosa) 



from Stonington, Conn., with an isolated tooth, showing resemblances 

 to such conodonts as Distacodus. 



7. Dermal plates of the recent shark Eulamia obtusa, X 20. 



8. Skin of another recent shark Platypodon, X 20, with small closely ar- 



ranged dermal plates. 



o 



