48 PROCEEDINGS COTTESWOLD CLUB 1907 
Distinction :—It does not attain the broad dimensions 
of C. pernummus, and has a narrower apical angle. 
Remarks :—Zieten’s shell is more excavate anteriorly ; 
Bayle’s shell is only truncate, but it slopes to a narrower 
anterior margin. 
Localities :—Somerset, Radstock. The large example 
from Mr Tutcher’s collection; two small specimens in 
Mr Marshall’s cabinet. The Davidson specimen is pre- 
sumably from Farringdon Gurney, near Radstock. Cal- 
vados, British Museum, Nos. 65402, 65599”; Tilly sur 
Seulles, my collection. 
4. CINCTA NUMMOSA, sf. x., Pl. V, figs. 17, 18. 
1905. Waldheima numismalis; Rau (non Valenciennes) 
Brach. Mittl. Lias Schwabens; Geol. Pal. Abh. 
N. F. VI, Pl. xxxiv, (iv), fig. 1, only. 
Description :—Subcircular, thin, anterior median portion 
of valves slightly flattened, and toward edge slightly ex- 
cavate, anterior margin excavate. Apical angle about 116. 
Distinction :—This form is similar to C. xammus, but 
it is not so broad, its outline is more circular, and it 
is more anteriorly excavate. 
Remarks :—This species seems to be the one most 
usual at Radstock; there are many specimens in Mr 
Tutcher’s and Mr Marshall’s collections, all shewing the 
peculiar lenticular shape with sharp edges even in adult. 
There is also a specimen in Mr Tutcher’s collection which 
may be a variety. It has the same form, but acquires 
slightly thickened edges in adult, that is when rather 
smaller than the example depicted in Pl. V, fig. 17. It 
shews several halts of growth, and is therefore, perhaps, 
a prematurely aged form. A half-grown specimen shews 
similar features. 
Localities and Stratum :—Somerset, Radstock ; various 
exposures around the town (Mr Tutcher, Mr Marshall, and 
Mr Richardson); some of the specimens are labelled 
