PLATE II. 
Fig. 1.—Carbonicola robusta. Transverse form from Limerigg Slamannan 
Collection of Mr. Smith of Kilwinning, Ayrshire. (Page 45.) 
Fig. 1a.—Carbonicola robusta. The same shell, showing interior and hinge 
of the right valve. «a. The edentulous anterior portion of the hinge-plate. 
b. Cardinal tooth somewhat bevelled at the expense of its lower border. c. Con- 
cavity for cardinal tooth of the left valve. d. Plain toothless surface of the 
posterior part of the hinge-plate. The unsinuated pallial sinus and posterior 
adductor scar, are also shown. (Page 45.) 
Fig. 2.—Carbonicola robusta. Small form from Shotts. Same Collection. 
(Page 45.) 
Fig. 3.—Carbonicola robusta. A more rotund form from Upper Coal-measures, 
Airdrie. Dr. John Young’s Collection. (Page 45.) 
Fig. 4.—Carbonicola robusta. Dalmellington. Dr. Hunter’s Braidwood Col- 
lection. (Page 45.) 
Fig. 5.—Carbonicola robusta. Quadrate form from Dalmellington. Dr. 
Hunter’s Braidwood Collection. (Page 45.) 
Fig. 5 a.—The same, showing cast of the interior and hinge-line. (Page 45.) 
Fig. 6.—Carbonicola robusta. Young form. Mr. Beveridge’s Collection. 
(Page 45.) 
Fig. 7.—Carbonicola rugosa. From Cant Clough, Burnley. Mr. George 
Wild’s Collection. (Page 49.) 
Fig. 8.—Carbonicola rugosa. From Hebden Bridge. Collection of the Geo- 
logical Survey, Jermyn Street. (Page 49.) 
Fig. 8a.—The same, showing external ligament and hinge-line. 
Fig. 9.—Carbonicola robusta. Hinge-plate of specimen from the Holly Lane 
Seam (?), Hanley and Bucknall Colliery, North Staffordshire. My Collection. 
(Page 45.) 
Figs. 10 and 11.—Carbonicola robusta. From the Shale above Stinking 
Coal, Froghall. My Collection. (Page 45.) 
