PLATE LVI. 



PAGE. 



AcANTHOLEPis PUSTUi.osus, Newb 38 



Fig. 1, la, Two cranial? plates in their relative j>o8itioiis Natural size. 

 16. Reduced outlines of four plates probably in tht-ir r-lative positions. 

 2. Interior sui-face of plate probably homologous with la. 

 3 Exterior surface of suialli strongly tuberetilated plate corret.pondiflg to \a. 



4. Triangular plate, probably one siAe of a flattenea spine. 



5. Slender spine, probably from body 



6. Eobust spine, with strongly squamose margin, from body? 



All the figures, except 16. are of the size of nature ; the originals from the Cornifeiouq lime- 

 stone at Delaware and Sandusky, Obio. 



