201 



(ler rod, and a sliallow raljbet along the Hat edge is occupied by a slender flat 

 rod. Of the tour principal rods, the two median are the most slender, and 

 llie flat maririiial the widest. Of the two median, that next the latter is tlu; 

 wider. Tlie stout marginal, or protiabl}' anterior, rod is segmented en chev- 

 ron, tlie angle directed disfally and lying near the free margin. The suture of 

 the resulting segments is entirely straight, except, when returning, it approaches 

 tlie margin, where it suddenly turns to the margin at right angles to it. The 

 next rod is segmented without chevron obliquely backward and inward ; 

 where it leaves and reaches the margins, it is at right angles to them, and the 

 margin projects obtusely at those points. Between the ends, the suture is very 

 irregular and jagged, sending processes forward and backward. The segmen- 

 tation of the next rod is similar, but more regularly serrate; distally, it becomes 

 as irregular as in the last. The transverse marginal termini of the sutures are 

 serrate in both. The inner and widest rod presents a still more regularly 

 serrate oblique suture with the truncate extremities; but, owing to the width 

 of the rod, the near approximation of the sutures continues for a longer 

 distance. When broken, the suture appears steplike. 



Measurements. 



M. 



Length of a iiagmeut of the (?) caudal spiue 0.25 



Width of the fragment at the iiroxinial fracture 0.06 



Greatest thickness at the i)n)xiuial fracture 0.013 



Width of the posterior rod at the proximal fracture 0. 0245 



Ijenj|;tU of six distal caudal vcrteb:!0 0. 1(1 



Width of tlie hicmal spine of the secoud of the series 0.024 



Vertical <lianietcr of tlie centrum of the first of the series 0.025 



Leugth of the ueural spine and centrum of the anterior caudal 0. 108 



Transverse diameter of the neural spine of the anterior caudal at the base 0.0235 



Antero-posterior diameter of the four anterior caudal neural spines in coutact 0. 069 



Li'iigth of the centrum of a dors.al 0.04 



Vertical diameter of a dorsal 0. 0015 



Transverse diameter of a dorsal (crushed) 0.041 



These remains were found in place by Prof B. F. Mudge; he states tiiat 

 their extent was eight feet. As they embrace no cervical vertebne nor por- 

 tions of cranium, two feet are probably to be added, giving a total of near ten 

 feet for the length of this fish. It was discovered at a point on llie bank of 

 the Solomon or NepahoUa River, in Kansas, one hundred and sixty miles 

 fiom its |)uinf ofjuiidioii with the Kansas River. 



POUTHICUS 1.ESTRIO, CopC. 



Represented l»y a porlinii of the cranium, including both niandil)iil;ir 



rami, and the maxillary and premaxillary bones of one side, all witli denlilion 

 2fi n 



