Cope. J 1J4 [Nov. 2, 



crown is obtuse, as is also the apex. The outline of the apex is rather 

 broadly acuminate. The enamel is closely and strongly rugose, longitudi- 

 nal^ on the base, transversely at the edges, and reticulately on the middle 

 portions of the crown. 



Measurements. M. 



Length of crown with portion of root 0. 120 



Diameter of root at middle 025 



Length of crown 055 



tv„ , , e (longitudinal 030 



• Diameter of crown < & 



\ transverse 020 



The crown of the second tooth is a little less expanded laterally, and has 

 a greater transverse diameter. The outer side is more convex, and there 

 are two marginal ribs on the basal half of the crown. The interior are 

 not strictly marginal, but are situated within the exterior ribs. Both are 

 very obtuse, and they are separated by a shallow groove. There is no 

 median longitudinal rib. 



Measurements. M. 



Diameter of crown at middle i anteroposterior 026 



{ transverse 018 



The third type is smaller in all its dimensions, and the crown is equal to 

 the root in long diameter. In my single specimen the distal portion of 

 the crown is lost ; the part which remains exhibits neither contraction 

 nor expansion of outline. The borders are very obtuse, and each surface 

 resembles a roll inwards which is bounded by a shallow parallel groove on 

 the inner face of the tooth. Between the grooves the surface is slightly 

 convex. The section is thus an oval with one side very little convex. The 

 enamel is thick and marked with longitudinal rugosities. 



Measurements. M. 



Length of fragment 060 



"root 030 



Diameter " ... 014 



tv„™~+, e , •■]„ (longitudinal 0135 



Diameter of crown at middle < ° 



'transverse 0085 



Tichosteus ltjcasanus, gen. et sp. nov. 



Char. gen. — The characters of this genus are derived primarily from the 

 vertebrae. They are nearly amphiplatyan, but one extremity of the articu- 

 lar face is slightly concave, while the other is still more slightly convex 

 or concave. The borders of the former are expanded, while those of the 

 latter are not enlarged. The centrum is hollow, but the chamber does not 

 communicate with the external median by a lateral foramen, as in Camara- 

 saurus. The neural arch is attached by suture. There is no capitular ar- 

 ticulation on the centrum. 



Char, specif. — There is no hypapophysis on either dorsal or lumbar ver- 



