BRACHIOPODA. 
123 
17. Thecidium Moorei. 
Shell subquadrate, smooth, attached by the whole surface of 
the ventral valve ; valves slightly indented in front ; front 
margins much thickened, steep ; dorsal valve almost flat ; lower 
valve with a well-defined triangular area ; deltidium large, ele- 
vated. Lon. 2, lat. 2, alt. 1 line. 
Thecidea Moorei, Davidson, 1851, 2Ion. Ool. Brack, p. 13. pi. 1. 
f. 10. 
Fossil. Lias (Marlstone). Ilminster, attached to Rhynckonellte. 
18. Thecidium Deslongchampsii. 
Shell u-regulai'ly oblong, smooth, attached by the truncated 
beak of the ventral valve ; ventral valve deep ; area wide, short 
and irregular ; deltidium indistinct ; dorsal valve subcircular, 
slightly convex, its- interior sm’face surrounded by a broad, gra- 
nulated border ; a single central septum divides the brachial ca- 
vities, in each of which there is a granulated lobe. Lon. 2, 
lat. H, alt. 1^ lines. 
Thecidea Deslongchampsii, Davidson, 1852, Ann. Nat. Hist. 
April, pi. 14. f. 6-9. 
Fossil. Lias. Normandy. 
