584 
PLATE LIX. 
. 1-2. HrLtopus crassus Davis, : 5 ‘ $ . 
1. Profile of posterior aspect of medium-sized tooth. 
1 a. View of the upper surface of crown from above. 
2. Profile of anterior aspect of tooth. 
2 a. Lateral elevation of the same tooth. 
Carboniferous Limestone, Armagh, . EL« coll. Enniskillen Collection. 
. 3, 4. HeLopus TENUuIS, Davis, 6 . ¢ : : 6 : 
3. Posterior aspect of the tooth. 
4. Anterior aspect of tooth imperfect on left extremity. 
4 a. Lateral elevation of same tooth. 
Carboniferous Limestone, Armagh, . . Hx coll. Enniskillen Collection. 
5, 6. Hetopus ciavatus, Davis, . . : . : . 6 
5. View of the upper surface of crown from above. 
6. Front view of another tooth. 
6 a. Side view of same tooth. 
Carboniferous Limestone, Armagh, . -. Ee coll. Enniskillen Collection. 
. 7. Hetopus acutus, Davis, . : g 5 : 0 6 0 
7 a. Lateral elevation of same specimen. 
Carboniferous Limestone, Armagh, . . Hx coll. Enniskillen Collection. 
. 8. HELODUS RICHMONDIENSIS, Davis, . : : ‘ 0 ‘ 6 
Anterior aspect. 
8 a. Side view of the same tooth. 
Carb. Limestone, Richmond, Yorkshire, . #x coll. Enniskillen Collection. 
. 9 HeELopus TRIANGULARIS, Davis, . : : 5 : 
Anterior or front view of the tooth. 
9 aw. Side view of the same tooth. 
9 }. Posterior or back view of the same tooth. 
Carboniferous Limestone, Armagh, . . Ex coll. Enniskillen Collection. 
Fic. 10. HeLopus expansus, Davis, 6 6 : 
,, 10a. Side view of the same specimen. 
Carboniferous Limestone, Armagh, . . Ex coll. Enniskillen Collection. 
Fic. 11. Heropus rupis, M‘Coy, . ; : : : 0 . 
» lla. View of the crown surface from above. 
Carboniferous Limestone, Ex coll. Museum Geological Society, London. 
Figs. 12-15. Pueuropus woopt, Davis, . 0 5 : . 
Carboniferous Limestone, Rie! anon Wonlkaitina, 
Hx coll. Wm. Horne, Esq., Leyburn ; ; Reed Collection, York Museum. 
Fics. 16-21. PETALODUS HASTINGSL&, Owen, 5 A ; . : : 
,, 16,19. Front views of average-sized specimens. 
, 16a. Longitudinal section of same tooth. 
,, 17. Posterior concave surface of another example. 
, 18, 20, 21. Distorted specimens, probably from the posterior extremity of the jaw. 
Mountain Limestone, Armagh, ‘ . Ex coll. Enniskillen Collection. 
Fics. 22, 23. PeraLopus acumINaATUus, Agass. 6 5 . . Si : 
» 22. Very large specimen—front view—base having the appearance of being divided 
like Polyrhizodus. 
Carboniferous Limestone, Richmond, Yorkshire, 
Ex coll. Reed Collection, York Museum. 
Fic. 24. PETALODUS ACUMINATUS, Agass., 
Carboniferous Limestone, Richmond, . Lx coll. Enniskillen Collection. 
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