DEVONIAN FISHES OF IOWA 109 



thick at the base, and indistinctly striated. The external den- 

 ticles are also stout in proportion to the size of the principal 

 cone, but the three intermediate denticles of either side are ex- 

 cessively small. The total height of the principal cone prob- 

 ably amounted to less than 1.5 cm, and the length of base is 

 estimated to have been about 2.5 cm. 



Formation and locality. Hamilton limestone ; Milwaukee, Wis- 

 consin. 



Cladodus coniger Hay. 



1889. Cladodus carinatus J. S. Newberry, U. S. Geol. Surv. Monogr. 16, p. 



103. 

 1899. Cladodus coniger 0. P. Hay, Amer. Nat. 33, p 783. 



In the original description of this species, the teeth are stated 

 by Newberry to be ''less than half an inch in breadth and height, 

 the base narrow, and bearing one central and four lateral cones, 

 the exterior pair larger than the intermediate ones, but all much 

 lower than the central denticle. ' ' The distinctive feature of the 

 species is said to consist in the presence of four moderately 

 strong carinations on the flattened posterior surface of the prin- 

 cipal cone. 



Teeth evidently belonging to this species are by no means 

 uncommon in the Chemung of Warren county, Pennsylvania, but 

 as a rule are imperfectly preserved. The general form is simi- 

 lar to that of C. concinnus Newberry, from the Huron shale of 

 Ohio; and as in that species, the pair of intermediate denticles 

 is sometimes absent. The external cones also diverge outwards 

 at a considerable angle. The principal cone is strongly com- 

 pressed, more or less recurved, with sharp lateral edges, and 

 prominently striated on both faces. The number of carinae 

 along the flattened, moderately convex anterior face is not lim- 

 ited to two pairs, however, some specimens displaying twice that 

 number. These are symmetrically arranged on either side of 

 the median line, the two innermost being nearly vertical and 

 rather more prominent than the rest. 



Formation and locality. Chemung beds (Chautauquan) ; War- 

 ren county, Pennsylvania. Also from the Meadville Upper 

 Shale (Waverly series), near Meadville in the same State. 



