130 PALEOZOIC FISHES OF NORTH AMERICA. 
The following is a list of the fishes found in the Cleveland shale up to 
the present time: 
1. Titanichthys Agassizii, Newb. | 15. Ctenacanthus Clarkii, Newb. 
2). Clarkii, Newb. 16. compressus, Newb. 
3. Dinichthys Terrelli, Newb. 17. Hoplonchus parvulus, Newb. 
4. intermedius, Newb. 18. Orodus elegantulus, Newb. 
5. minor, Newb. 19. Polyrhizodus modestus, Newb. 
6. Gouldii, Newb. 20. Cladodus concinnus, Newb. 
Zhe corrugatus, Newb. 21. Kepleri, Newb. 
8. curtus, Newb. 22. parvulus, Newb. 
9. Glyptaspis verrucosus, Newb. 23. Fyleri, Newb. 
10. Diplognathus mirabilis, Newb. 24. Terrelli, Newb. 
11. Mylostoma Terrelli, Newb. ) psy tumidus, Newb. 
12 variabilis, Newb. | 26. Ctenodus Wagneri, Newb. 
13. Trachosteus Clarkii, Newb. | 27. Phaebodus politus, Newb. 
14. Ctenacanthus vetustus, Newb. 28. Actinophorus Clarkii, Newb. 
Order PLACODERMI. 
Genus TITANICHTHYS, Newb. 
In 1883 Mr. Jay Terrell, of Sheffield, Lorain County, Ohio, found in 
the Cleveland shale, which had yielded to him so many bones of Dinichthys, 
the cranium and some body plates of a Placoderm fish of still more gigantic 
size. While evidently belonging to the family of Dinichthide it was 
generically distinct, and I gave it the name of Titanichthys. 
As in Dinichthys, the head is triangular in outline, but the largest 
cranium of the largest known species of that genus, D. Terrelli, measures 
but three feet across the occiput, while the cranium of Titanichthys has a 
breadth of four feet or more. 
The cranial surface, as in Dinichthys, is granulated or nearly smooth, 
and is ornamented with a series of incised lines or grooves (‘Schleim 
Caniile”), which form a distinct and somewhat graceful pattern. 
The dorsomedian shield is rounded.in outline, about two feet in diame- 
ter, much thinner than that of Dinichthys, and with a long and relatively 
slender process, which reaches backward and downward apparently to gain 
the support of the neural spines. 
The supra-scapulas are, as in Dinichthys, quadrangular or trapezoidal, 
lighter than those of Dinichthys, but broader; their longest diameter being 
from eighteen to twenty inches. They articulate with the cranium by a 
