PLA T Pee ay 
ARCHZOBATIS GIGAS, Newb. (p, 194). 
Fics. 1,2. Third and fourth teeth of series represented on Pl. XXII. 
3. End view of second tooth, natural size. 
Greencastle, Ind. 
CTENACANTHUS COMPRESSUS, Newb. (p. 168). 
4, Spine, basal portion, natural size. 
4°. Section at middle. 
4>, Ornamentation enlarged. 
Cleveland shale, Sheffield, Ohio. 
GYRACANTHUS INORNATUS, Newb. (p. 177). 
5. Spine, summit, much worn, 
Cuyahoga shale (Waverly), Knox County, Ohio. 
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