366 University Geological Survey of Kansas. 



more or less with each other, and give the outer surface of the 

 bone a somewhat net-like appearance. 



Length of rostral fragment 199 mm. 



Transverse diameter 136 mm. from distal extremity 34 " 



Transverse diameter 22 mm. from distal extremity 22 " 



Protosphyraena recurvirostris. 



Protosphyroena recurvirostris Stewart, Kans. Univ. Quart., vol. vn a, 

 pp. 191, 192. 



The material upon which this species was based consists of a 

 complete rostrum, No. 373, with the adjoining portions of the 

 vomer and parasphenoid, and differs from P. nitida in the fol- 

 lowing characters : The superior distal surface is regularly 

 rounded and not flat, as in that species, and the cross-section at 

 this point is round instead of semicircular or oval. The speci- 

 men corresponds in some respects with the rostrum of P. 'pene- 

 trans, and is more closely related to this species than to any of 

 the other forms that have been described. I was inclined to 

 it call P. penetrans until I found a rostrum of that species, when 

 I discovered that it differed from it in a number of points which 

 were sufficiently great to be called specific. The rostrum is more 

 slender as a whole and is contracted to a more acute point than 

 in P. penetrans. The markings are more sharply defined and 

 the ridges inosculate with each other but rarely. In P. pene- 





Rostrum of Protosphyrcena recurvirostris , one-half actual size. 



trans the markings are more or less reticulate. In the anterior 

 portion of the species under consideration the ridges are closely 

 placed to each other, while posteriorly they become scattered and 

 are not so well marked as in the anterior portion of the bone. 

 Their direction also becomes more varied in this region. On 

 the posterior half of the inferior surface, the ridges become less 



