PLATE XxX: 
ASTEROSTEUS STENOCEPHALUS, Newb. (p. 44). 
Fig. 1. Cranium seen from above, outline completed from another specimen, natural size. 
Corniferous limestone, Sandusky, Ohio. 
COCCOSTEUS OCCIDENTALIS, Newb. (p. 52). 
2. Dorsomedian plate. 
2°, Ventromedian plate, inside. 
COCCOSTEUS DECIPIENS, Ag. 
3. Dorsomedian plate. 
4,4. Ventromedian plate, outside and inside views. 
Devonian limestone, Scotland. 
LIOGNATHUS SPATULATUS, Newb. (p. 52). 
5. Mandible. 
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