556 
PLATE XLV, 
Fic. 1. CrenacaNTHUS L&VIS, Davis, 5 : ; : : : 3 
,. 1a. Section of the upper portion of the same. 
Limestone, Armagh, 5 ; Ex coll. Enniskillen Collection. 
Fic. 2. CTENACANTHUS PUSTULATUS, Davis, é ; . : F 
Limestone, Armagh, . : Ex coll. Enniskillen Collection. 
Fig. 3. CTENACANTHUS SULCATUS, Agassiz, . : - : . ° 
», 3a. Section of the upper part of the spine. 
Limestone, Bristol, b 0 ‘ Ex coll. Bristol Museum. 
Fig. 4. CrenacanTuHus piicatus, Agassiz, é . ° 6 : . 
» 4a. Enlarged representation of the surface striation. 
» 4band 4c. Sections across the spine. 
Limestone, Armagh, : . Ex coll. Geological Society’s Museum. 
Fig. 5. Crenacantuus (OncHus) rectus, Agassiz, MSS., 0 : : : 
Limestone, Armagh, : Ex coll. Geological Society’s Museum. 
Fic. 6. CrENACANTHUS CRENULATUS, Agassiz, MSS., . é 9 : 
», 6a. Section across the same. 
Limestone, Armagh, .  Ezxcoll. Woodwardian Museum, Cambridge. 
Fia, 7. ACONDYLACANTHUS COLEI, Davis, . F 3 ‘ ‘ 0 : 
», «a. Transverse section. 
Limestone, Armagh, : ; . Fx coll, Enniskillen Collection. 
Fia. 8. AcoNDYLACANTHUS TENUISTRIATUS, Davis, : 6 : é 6 
» 8a. Transverse section. 
» 8b. Part of surface enlarged. 
Limestone, Armagh, 6 6 Ex coll. Enniskillen Collection. 
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