174 PALEOZOIC FISHES OF NORTH AMERICA. 
has interesting relations with Cladodus on the one hand and Diplodus on the 
other; constituting in some sort a connecting link between them. In 
Cladodus the central cusp is always largest and often greatly preponderates 
over the lateral ones. In Diplodus, on the contrary, the lateral denticles are 
always very much larger than the central, and this latter is not unfrequently 
quite obsolete. In Phwbodus, however, the crown supports three cusps which 
are of nearly equal size. 
The only other teeth known similar to these are those of which the 
name of Phabodus Sophie has been given by St. John and Worthen,! and 
obtained from the middle Devonian of Waterloo, Iowa. From that species 
ours may be readily distinguished by its larger size and its more elongated, 
recurved, and equal cusps. The concave base is also somewhat notched 
posteriorly in our species, and instead of a double pad under the anterior 
border it has a narrow and accurately defined arch. 
The teeth which formed the basis of the above description were found 
by Messrs. Frank Wagner and Jay Terrell in the Cleveland shale near the 
mouth of Black River, Lorain County, Ohio. They exhibit considerable 
range of size, the larger being twice as high and broad as the smaller, and 
in the larger teeth the polished surface of the cusps is free from striations, 
while in the smaller form there are a few relatively coarse raised lines on 
the anterior face of the cusps and base. In other respects they are so 
much alike that it has not been thought best to distinguish them by different 
specific names. Their affinities to Cladodus are shown by the general form 
of the base and by the pad-like prominence which occupies the central por- 
tion of its upper surface. This feature is quite common among the species 
of Cladodus, but the teeth under consideration are distinguished from all 
members of that generic group by the great development of the lateral cusps, 
which are perhaps a little larger than the central one. 
ACTINOPHORUS, nov. gen. 
Tile-scaled Ganoids, of medium or large size, long and slender; body 
cylindrical ; head pointed, bony ; teeth numerous, conical, acute; fins with- 
out fulera, delicate, many-rayed; scales narrow, quadrangular, thin. 
1Geol. Survey of Illinois, vol. 6, p. 251, pl. 1, figs. 14-144. 
