PLATE I. 



Fig. 1. — Modlola iKitula. A right valve showing the contour of the posterior 

 end. In the Geological Collection of the Belfast Museum. (Page 58.) 



Fig. 2. — Modlola patula. A left valve from the Limestone of Co. Cork. In 

 the Collection of Mr. J. Wright, of Belfast. (Page 58.) 



Fig. 2 a. — Modiola ])afula. To show the upper surface of the same shell. 

 (Page 58.) 



Fig. 2 /;. — Modiola patula. Tbe contour line of the valve from above 

 downwards. (Page 58.) 



Fig. 3. — Lithodomus lingualis. A left valve from Co. Cork. In the Collection 

 of Mr. J. Wright. (Page 74.) 



Fig. 4. — Lithodomus lingualis. A left valve. One of the types of Mr. 

 R. Etheridge's Modiola lithodomoides. From the Limestone of Park Hill near 

 Longnor. In the Collection of the Geological Survey, Jermyn Street. (Page 74.) 



Fig. 4 a. — Lithodomus lingualis. Showing the view from above. (Page 74.) 



Fig. 5. — Lithodom,us lingualis. A right valve from the Limestone of St. 

 Dooghlas' Quarry, Co. Dublin. My Collection. (Page 74.) 



Fig. 6. — Jjithodomus lithodomoides. A fairly perfect example from the Carbo- 

 niferous Shales of Beith, Ayrshire. In tbe Collection of Mr. J. Neilson, Glasgow. 

 (Page 78.) 



Figs. 6 a, 6 h. — Ijithodom,us litJiodomoides. Two views of the same specimen 

 one from above and the latter from below. (Page 78.) 



Fig. 7. — lAtliodomus lithodomoides. A more perfect example from the same 

 locality and Collection. (Page 78.) 



Fig. 8. — Lithodomus lithodomoides. A specimen from the same locality 

 showing the elongated escutcheon, very much developed. Presented to me by 

 Mr. R. Craig, of Beith. (Page 78.) 



