196 Proceedings of the Roijal Physical Society. 



Genus Cheirodota (Eschscholtz), 1829. 

 Cheirodota (J) Traqicairii, Sp. nov. — (PL YI., Fig. 1). 



Sp. Char. — Concavo-convex wheel-like plates, with a very 

 slightly undulating margin, and a central space occupied by 

 four more or less triangular perforations ; outer zone sub- 

 divided by eight short septa or spokes, into a corresponding 

 number of semicircular or semi-oval perforations, with plain 

 margins. The diameter is about "01, or i^th of an inch ; 

 the central space is about '0035, or y^^ths of an inch. 



Ols. — C. (J) Traqiiairii may be at once distinguished from 

 the forms which follow by its scarcely undulating outline, 

 semicircular perforations of the outer zone, and the four- 

 perforated centre. The four perforations in the centre appear 

 to correspond with every other subdivision or spoke. My 

 indebtedness to Dr E. H. Traquair, for assistance and advice, 

 always kindly rendered, affords me an opportunity of associ- 

 ating his name with this form. 



Loc.and Horizon. — Limekilns, old quarry, near East Kilbride, 

 Lanarkshire (the original locality), in shales of the Calderwood 

 Limestones, Lower Carboniferous Limestone Group. Wood- 

 end Quarry, near Fordel, Fife, as before. Orchard Quarry, 

 near Glasgow, shale above the Orchard Limestone, Upper 

 Carboniferous Limestone Group (Mr D. Eobertson, F.G.S.). 



Cheirodota (?) Robertsoni, Sp. nov. — (PI. VI., Fig. 2). 



Sp. Char. — Wheel-like plate, concavo-convex, with a central 

 undivided (?) space, separating spaces or " spokes," straight, 

 and rod-like ; perforations few in number, six to eight, and 

 acutely triangular. 



Obs. — This appears to be quite distinct from the last species 

 in having the central space filled in, and the marginal per- 

 forations triangular in form. I am indebted to Mr David 

 Eobertson, F.G.S., of Glasgow, for specimens of this and the 

 preceding species, and after whom the present one is named. 



Loc. and Horizon. — Capelrig Old Quarry, near East Kil- 

 bride, Lanarkshire, in shales of the Calderwood Limestones, 

 Lower Carboniferous Limestone Group. 



Cheirodota (?) priiiiceva, Sp. nov. — (PL VI., Figs. 3-8). 

 Sp. Chars. — Plates concavo-convex, margin unduLating ; 



