ON NEW BRACHIOPODA. 115 
rare species occurs, S. Ilminsteriensis. This hitherto has 
been supposed the highest point reached by the spirifer, 
but the discovery of a species at Dundry carries its range 
into the oolitic period. 
SPIRIFER OOLITICA.—Moore.—Plate 3, fig. 13—14. 
Shell very minute, usually much broader than long, 
having nine distinet plications, graduating regularly from 
central one which is in relative proportion to the others ; 
without defined sinus ‘or fold ; punetuations not distin- 
guishable. Interior of valves smooth; dorsal valve having 
large and deep dental sockets; ventral valve having no 
perceptible central septum. 
Obs. This little species is abundant in the inferior 
oolite of Dundry, and it also occurs at Seavington, near 
Ilminster. 
Family„—THECIDEIDE. 
Genus—THECIDEUM.— Defrance. 
The oldest forms of this genus in England are from the 
middle lias, from which formation I obtained three species 
in 1849, viz., Thecideum Bouchardü, Dav.; T\. Moorei, Dav.; 
and T. triangularis, D’Orb.; which, with 7. rustica, Moore, 
from the upper lias, and 7. Dickinsonii, Moore, from the in- 
ferior oolite, comprised all the then known oolitie species. 
With the exception of the latter, these species have since 
been found by M. Eugene Deslongchamps in the upper lias 
of France; and that zealous geologist has found associated 
with them seven other species, so that the list has thus been 
considerably increased. Two liasic forms, 7. Bouchardü, 
and 7. triangularis, pass into the inferior oolite of Dundry, 
