BUTFALO SOCIETY OF NATURAL SCIENCES 



159 



and the outer face striated. Height of largest of the three teeth 

 preserved in type specimen greater than width of element in region 

 of this tooth. Teeth well separated but distance between adjacent 

 teeth less than width of one of the teeth. Spine ornamented with a 

 few longitudinal striations (mostly worn off in the type specimen). 



Remarks. — This species is distinguishable at a glance from Apatea- 

 canthus vetustus (Clarke), by the fact that the teeth are vertical instead 

 of inclined. From A . peculiaris (Hussakof ) the present species dififers 

 in the teeth being narrower in proportion to their height, and in 

 being strongly striated. It is possible, however, that in the latter 



/\/\A z^^ 



Fig. 54. Ay Atopacanthus dentatus, n. gen., n. spec. Type, Natural Size. E 2496. 



B, Atopacanthus peculiaris (Hussakof.) For Comparison; Reversed 



Right to Left. 



species, perfect specimens showing the external surface of the teeth, 

 not merely their impression, would also show the teeth to have been 

 striated. 



Ctenacanthus nodocostatus, n. sp. 



(PI. 51, fig- i) 



E 2083 Type. — Impression in sandstone of a complete spine, 17 cm. 

 in length. 



Formation and Locality. — Yellow sandstone above ' 'Second Moun- 

 tain Sandstone" (CatskiU); 4 miles South of Pleasantville, Venango 

 County, Pa. Collected by J. F. Carll. 



Spine of medium size, gently arcuate, with a large inserted portion, 

 occupying about \ the entire length of the spine. Lateral faces orna- 



