ON THE CHARACTERS OF SOME PALEOZOIC FISHES. 



r.v 

 E. D. Cope. 



(^VVitb Plates xxviii— xxvin. > 



I. — On a new l^LAS.MOBRANCII FROM Till: I'EUMIAX. 



Styptobasis kniglitiana Cope. Oen. et sp. i:ov. Fi<j. 1. 



Char. Gen : The single tooth which represeuts this geuus has an 

 eh)ngate compressed crown with two opi)osite simple cutting edges. 

 Botli faces are convex, the one much more so than the other. No hit- 

 eral processes or denticles. The most remarkable peculiarity is in the 

 root; it is very small, having no greater width than the crown, and 

 contracting from the base of the crowu to a truncate termination but 

 a little distance removed from the former. 



The crown of the tooth resembles that of an Oxyrhina, but the root 

 is totally different. In this respect it resembles a Dendrodus. 



Char. Specif.: Cutting edges of tooth continued to base of crown. 

 Surface of crown everywhere smooth. Truncate extremity of root a 

 crescent with obliquely truncate horns with coarsely rugose surface. 

 "Where the cutting edges are vertical their surface is below the more 

 convex side of the crown. The root has a lateral edge at each side, 

 which extends obliquely from below the cutting edge to the lateral 

 angle of the truncate base, and is marked ofit" from the base of the 

 crown by a constriction. The base of the crown is openly emarginate 

 by an angle of this constriction. On each side of this emargination 

 the surface is transversely wrinkled. On the same side the root is 

 similarly wrinkled ; on the opposite side the wrinkling is less distinctly 

 transverse. 



Measiiremeiih. 



Millinieter.s. 



Total elevation of tooth 025 



Elevatiou of crowu ' '20 



Diameters of crowu al)Ovo base : 



Longitudinal Oil 



Transverse 005 



Diameter of root: 



Longitudinal 012 



Transverse 0C6 



If this species be a Cladodont shark, which is quite po.ssible, it agrees 

 with Lambdodus St. .1. and W. in its single simple crown, but that 



Proceediuga Xatioual AIuscuiu, Vol. XIV — Xo. 866. 



447 



