1870.] ^^'^ [Cope. 



M 



Long diameter of spine 0.0345 



Basal " " 019 



Lengtla, two cervicals (not distorted) 033 



Diameter of the anterior 021 



Length of a dorsal ... .016 



" " caudal 014 



Width neural spine of caudal, at base 012 



Length alveolar margin premaxillary 022 



" anterior " " 02 



Depth from condyle of maxillary .^ 026 



Length crown premaxillary tooth 0043 



Diameter" " " 002 



A fragment of a large fiat bone exhibits very delicate radiating grooves 

 which are marked by spaced impressed dots. 



From the upper Cretaceous of Kansas, six miles south of the town of 

 Sheridan. Prof. B. F. Mudge. This species was about two thirds the 

 size of the species last described. 



Saijrocephai,us attdax. Leidy, sp. 



Xiphaciiniis audax. Leidy. Proc. A. N. Sci. Phil. 1870, 13. 



Established on a pectoral spine, supposed by Leidy to be that of a 

 Siluroid. According to the description, it does not differ from that of 8. 

 prognatJius in more than specific characters. Thus the anterior margin 

 is weakly serrate in the latter, a feature not described by Leidy in the 

 former. In ;S'. audax the posterior portions of both sides are said to be 

 grooved , in that part of the spine of 8. prognathus preserved, one surface 

 only exhibits the groove in question, one of whose edges is obliquely 

 ridged, as in 8. audax. From Kansas ; museum Smithonian. 



SAUKOCEPnALUS THAUMAS. Cope sp. nov. 



This is larger than any of the species here described. It is represented 

 by wholes or parts of from seventy to eighty vertebrae, with numerous 

 neural and hsemal spines and fin radii, and perhaps some ribs. There 

 are no teeth nor cranial fragments. The bulk of the vertebrae is double 

 that of those of 8. pJilebotomus, and appropriate to an animal of the 

 size of the 8. lanciformis. It may be ultimately found to be identical 

 with that species ; but there is no evidence conclusive of such a view at 

 present in my possession. 



The vertebras present the usual two inferior, two lateral, and two 

 superior grooves — the last for the neural arch. There are no cervical 

 vertebrae, for these characters show them all to be dorsals and caudals. 

 The suture for the neurapophyses forms a regular angulate convexity 

 projecting downwards. The arch is not closed above anteriorly, and is 

 expanded laterally, while the spine is directed very obliquely backwards. 

 The concavities of the articular extremities are equal in the dorsals ; but 

 in the caudals one surface is much more deeply concave than the other, 

 one being funnel-shaped, and the other nearly plane in a few. 



