314 The American Geologist. November, 1894 
Paleozoic fishes of North America.* In the first of these he 
gives an outline figure of Pander's restoration of the ventral 
armor of Coccosteus, which is here reproduced (fig. 1), ac- 
Fig. i. Ventral armor of Coccosteus decipiens Ag. Natural size. 
(Pander's restoration.) 
companied Iry a similar outline of the ventral armor of Dinich- 
thys, also herewith reproduced (fig. 2). In both these figures 
it will be seen that there is an anterior pair and a posterior 
pair of ventral plates. On the median line there is, in the 
case of Coccosteus, a lozenge-shaped bone in the center, over- 
lapped by both pairs of ventral plates, while anteriorly there 
is a triangular bone, the "antero-ventro-median." On the me- 
dian line of the Dinichthys armor there is apparently only one 
elongated bone which corresponds in position with the two 
medians of Coccosteus. The ventral armor of Dinichthys was 
thus supposed to consist of these five bony plates: 
One pair of anterior ventrolaterals, 
One pair of posterior ventrolaterals, 
One ventro-median. 
*U. S. Geol. Survey, Monographs, vol. xvir. 
