158 PALEOZOIC FISHES OF NORTH AMERICA. 
tation, that they will be easily recognized wherever seen. Doubtless the 
head with its jaws and teeth will soon be found by its indefatigable discov- 
erer, and it will then be possible to give a more complete description of it. 
Among the other fish remains associated with the plates of Glyptaspis in the 
Cleveland shale are two, of which the jaws and teeth are the only parts yet 
known, viz, Diplognathus and Mylostoma, and it is quite possible that the 
plates of Glyptaspis will be found in such relation with one or the other 
that we may be sure they once belonged together. This is not certain, 
however, as there are indications from fragments found that the fish fauna 
of the basin in which the Cleveland shale was deposited contained other 
genera and species than those already described. 
GLYPTASPIS VERRUCOSUS, N. sp. 
Plate XIII, Figs. 1, 2. 
Ventromedian plate broad-lanceolate, acute at one end, obtuse at the 
other, fifteen inches long by seven broad; central portion of outer surface 
forming a halbert-shaped figure coarsely tuberculated or ridged by lines of 
confluent tubercles, margins beveled to an edge, forming a band, an inch 
or more in breadth on every side; this slope is smooth or striated, evidently 
by the overlap of other plates, of which probably four surrounded the 
central one. The median plate, like others forming the armor, is from «a 
quarter to half an inch thick, of dense bony tissue, the tuberculated portion 
being covered with a sheet of enamel. 
A number of plates or pieces of plates ornamented like the ventro- 
median, and therefore from fishes of the same species, have been found by 
Mr. Terrell in the Cleveland shale; the first fragment many years ago. 
They are generally broken and sometimes bear marks of the great teeth of 
Dinichthys Terrelli, evidently the tyrant and terror of the bay or gulf in 
which the Cleveland shale was deposited. 
When entire these plates must have been long-elliptical in outline and 
unsymmetrical; therefore are not from the median line of the back. The 
central portion of the outer surface carries the strong and peculiar orna- 
mentation of the ventromedian plate, but this is surrounded by a sloping 
margin an inch in width which reaches to an acute edge. This margin is 
