618 



HISTORICAL GEOLOGY. 



The Coccosteus family was represented by species of large size. The 

 ventral plates of two are represented on page 616. Fig. 963 is Holonema 

 rugosum of Claypole ; as determined by H. S. Williams, the central plate 

 in the ventral shield (m. v.) has a length of 8t} inches. The specimen figured 

 is from the Oneonta sandstone, near Oxford, N.Y. In the related species, 

 Fig. 964, from Campbelltown, New Brunswick, the central plate is but one 



inch long. 



970-974. 



Ganoids. — Fig. 970, Glyptolepis Quebecensia (x|); 971, Eusthenopteron Foordi (xj); 972 , scale from a species 

 of Holoptychius ; 973, tootli, id. ; 974, Chirolepls Canadensis. Figs. 970, 971, 974, Whiteaves ; 972, 973, Leidy. 



The Dipnoans, or "Lung-fishes," Avere represented by gigantic species 

 called by Newberry Diniclithys and Titamchthys, from their size and formi- 

 dable dental armature. The species of Dinichthys, to which Figs. 965, 966 



