PLATE XVIII. 



Fig. 1. — Aviculopeden Losseni. A left valve. Froui Angram Brook, Pendle Hill. My Collection. 

 (Page 80.) 



Fig. 2. — Aviculopeden Losseni. A left valve. Same horizon. My Collection. (Page 80.) 



Fig. 3. — Aviculopeden Forbesii. A right valve, somewhat sheared. From Little Island, co. Cork. 

 Mr. J. Wright's Collection. (Page 83.) 



Figs. 4, 5. — Aviculopeden Forbesii. Same locality and Collection. (Page 83.) 



Fig. 6. — Aviculopeden Forbesii. Two left valves. Same locality. York Museum. (Page 83.) 



Fig. 7. — Aviculopeden Forbesii. M'Coy's type. From Millicent, Ivildare. In the Griffith Col- 

 lection, Science and Art Museum, Dublin. (Page 83.) 



Figs. 8, 9. — Eumicrotis ovalis. The right and left valves, which have slipped past each other, of 

 a specimen. From Settle. In the Woo dwardian Museum, Cambridge. (Page 46.) 



Fig. 10 — Aviculopeden deornatus. A right valve. From Little Island, co. Cork. Mr. J. Wright's 

 Collection. (Page 100.) 



Figs. 11, 12. — Aviculopeden deornatus. A left and a right valve. Same locality and Collection. 

 (Page 100.) 



Figs. 13, 14. — Aviculopeden deornatus. The left and right valves of a bivalved example. Same 

 locality and Collection. (Page 100.) 



Figs. 15 — 17. — Aviculopeden macrotis. Three left valves. From Little Island, co. Cork. Mr. J. 

 Wright's Collection. (Page 84.) 



Fig. 18. — Aviculopeden macrotis. A right valve, M'Coy's type. From Bruckless, co. Donegal. 

 Griffith Collection, Museum of Science and Art, Dublin. (Page 84.) 



Fig. 19. — Aviculopeden decussatus. A left valve, M'Coy's type. Preserved in the Museum of 

 Science and Art, Dublin. (Page 79.) 



Fig. 20. — Aviculopeden decussatus. A left valve, the type of Pecteti tripartitus, M'Coy. Same 

 Collection. (Page 79.) 



Fig. 21. — Syncydonema Sowerbyi. A left valve. No. 123 in the Woodwardian Museum, Cam- 

 bridge. (Page 118.) 



Fig. 22. — Syncydonema Sowerbyi. A left valve. From the Yoredale Series of Swaledale. 22a. 

 An enlarged area showing zigzag markings, due to removal of the outer layers of the shell. (Page 118.) 



Fig. 23. — Syncydonema Sowerbyi. A specimen with straight ears. From Poolvash, Isle of Man. 

 (Page 118.) 



Fig. 24. — Syncydonema Sowerbyi. A full-grown shell, left valve. From Hill Bolton, Yorkshire. 

 My Collection. (Page 118.) 



Fig. 25. — Syncydonema Sowerbyi. A fragment to show the great elevation of the ears. From 

 Cork. In the Collection of Mr. J. Wright. (Page 118.) 



Fig. 26. — Syncydonema Sowerbyi. M'Coy's type. From Howth, co. Dublin. In the Griffith Col- 

 lection, Museum of Science and Art, Dublin. (Page 118.) 



