OF CONCHOLOGT. 281 



Genus METOPTOMA, Phillips. 



Metoptoma, Phil., Geol. Yorksh. ii, p. 223, 1836. Leonh. 



and Bronn., Jahrb. p. 750, 1841. Morris, Br. foss. p. 



151, 1843. Woodw., Man. p. 155. Stoliczka, Pal. In- 



dica, ii, p. 324. Eichw., Leth. Ross, i, p. 1098. 

 Not Deslongehampsia, as per Chenu, Man. de Conchyl. i, p. 



376 ; nor Patella, lb. i, p. 375, fig. 2281. 



Shell patelliform, scar horseshoe shaped ; apex subcentral, 

 shell, truncate behind the apex, with the posterior margin broadly 

 emarginate or waved, and the anterior slope the longest. 



Type 31. piJeus, Phil., 1. c. p. 224, pi. xiv, f. 7. Carb. lime 

 stone, Great Britain. 



This genus, characterized by the extraordinary posterior trun- 

 cation, is only known from the older rocks in a fossil state. 



Chenu wrongly places it as a synonym of Deslongchampsia, 

 McCoy, (though having eighteen years priority !) with which it 

 cannot be aflfiliated. His figure of Patella Solaris, de Kon., 

 represents a typical 3Ietoptoma, but not the type of the genus, a 

 statement I wrongly attributed to Mr. Meek, in this Journal vol. 

 vi, p. 20. Stoliczka compares Capulus Troseheli, Mull., from 

 the Aachen cretaceous beds, with 3fetoptoma, which it appears 

 to resemble. A number of the species referred by Billings (Pal. 

 Foss. Can. Geol. Survey) to this genus, are evidently not conge- 

 neric. 



LIST OF FIGURES. 

 Plate 14. 



1. Acmcea mitra, Esch. Original. 



2. " virginea, Miill. Confirmed from Loven's figure. 



3. " insessa, Hinds. Original. 



4. Collisella patina, Esch. Original. 



5. " strigatella, Cpr. Original ; a, uncinus. 



6. • " pelta. Esch. Original. 



7. " asmi, Midd. Original ; a, uncinus. 



8. " persona, Esch. Original. 



9. " '' mitella, Mke. Original. 



10. " spectrum, Rve. Original. 



11. " fascicular' is, Mke. Original. 



12. " scahra, Rve. Original ; a, uncinus. 



13. " testudinalis, Mlill. Original. 



14. " subrugosa, D'Orb. Original. 



15. " atrata, Cpr. Original ; a, uncinus. 



